diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 7ac026673..694a6d635 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -9,6 +9,8 @@ Version 4.3.2
 
 - Added support for FreeBSD. Z3 can be compiled on FreeBSD using g++. 
 
+- Added support for Python 3.x.
+
 - Reverted to `(set-option :global-decls false)` as the default. In Z3 4.3.0 and Z3 4.3.1, this option was set to true.
   Thanks to Julien Henry for reporting this problem.
 
@@ -26,6 +28,29 @@ Version 4.3.2
 
 - Fixed crash reported at http://z3.codeplex.com/workitem/10
 
+- Removed auxiliary constants created by the nnf tactic from Z3 models.
+  
+- Fixed problem in the pretty printer. It was not introducing quotes for attribute names such as |foo:10|.
+
+- Fixed bug when using assumptions (Thanks to Philippe Suter and Etienne Kneuss)
+  Consider the following example:
+      (assert F)
+      (check-sat a)
+      (check-sat)
+  If 'F' is unstatisfiable independently of the assumption 'a', and 
+  the inconsistenty can be detected by just performing propagation,
+  Then, version <= 4.3.1 may return
+      unsat
+      sat
+  instead of
+      unsat
+      unsat
+  We say may because 'F' may have other unsatisfiable cores.
+
+- Fixed bug reported at http://stackoverflow.com/questions/13923316/unprintable-solver-model
+
+- Fixed timers on Linux and FreeBSD.
+
 Version 4.3.1
 =============
 
diff --git a/examples/c++/example.cpp b/examples/c++/example.cpp
index ab6e67ab9..9e92d99ab 100644
--- a/examples/c++/example.cpp
+++ b/examples/c++/example.cpp
@@ -812,6 +812,68 @@ void tst_visit() {
     visit(f);
 }
 
+void incremental_example1() {
+    std::cout << "incremental example1\n";
+    context c;
+    expr x = c.int_const("x");
+    solver s(c);
+    s.add(x > 0);
+    std::cout << s.check() << "\n";
+    // We can add more formulas to the solver
+    s.add(x < 0);
+    // and, invoke s.check() again...
+    std::cout << s.check() << "\n";
+}
+
+void incremental_example2() {
+    // In this example, we show how push() and pop() can be used
+    // to remove formulas added to the solver.
+    std::cout << "incremental example2\n";
+    context c;
+    expr x = c.int_const("x");
+    solver s(c);
+    s.add(x > 0);
+    std::cout << s.check() << "\n";
+    // push() creates a backtracking point (aka a snapshot).
+    s.push();
+    // We can add more formulas to the solver
+    s.add(x < 0);
+    // and, invoke s.check() again...
+    std::cout << s.check() << "\n";
+    // pop() will remove all formulas added between this pop() and the matching push()
+    s.pop();
+    // The context is satisfiable again
+    std::cout << s.check() << "\n";
+    // and contains only x > 0
+    std::cout << s << "\n";
+}
+
+void incremental_example3() {
+    // In this example, we show how to use assumptions to "remove" 
+    // formulas added to a solver. Actually, we disable them.
+    std::cout << "incremental example3\n";
+    context c;
+    expr x = c.int_const("x");
+    solver s(c);
+    s.add(x > 0);
+    std::cout << s.check() << "\n";
+    // Now, suppose we want to add x < 0 to the solver, but we also want
+    // to be able to disable it later.
+    // To do that, we create an auxiliary Boolean variable
+    expr b = c.bool_const("b");
+    // and, assert (b implies x < 0)
+    s.add(implies(b, x < 0));
+    // Now, we check whether s is satisfiable under the assumption "b" is true.
+    expr_vector a1(c);
+    a1.push_back(b);
+    std::cout << s.check(a1) << "\n";
+    // To "disable" (x > 0), we may just ask with the assumption "not b" or not provide any assumption.
+    std::cout << s.check() << "\n";
+    expr_vector a2(c);
+    a2.push_back(!b);
+    std::cout << s.check(a2) << "\n";
+}
+
 int main() {
     try {
         demorgan(); std::cout << "\n";
@@ -842,6 +904,9 @@ int main() {
         tactic_example9(); std::cout << "\n";
         tactic_qe(); std::cout << "\n";
         tst_visit(); std::cout << "\n";
+	incremental_example1(); std::cout << "\n";
+	incremental_example2(); std::cout << "\n";
+	incremental_example3(); std::cout << "\n";
         std::cout << "done\n";
     }
     catch (exception & ex) {
diff --git a/examples/python/example.py b/examples/python/example.py
index a8a764a4d..879c17c43 100644
--- a/examples/python/example.py
+++ b/examples/python/example.py
@@ -4,5 +4,5 @@ x = Real('x')
 y = Real('y')
 s = Solver()
 s.add(x + y > 5, x > 1, y > 1)
-print s.check()
-print s.model()
+print(s.check())
+print(s.model())
diff --git a/scripts/mk_util.py b/scripts/mk_util.py
index 381f92def..268a6d27b 100644
--- a/scripts/mk_util.py
+++ b/scripts/mk_util.py
@@ -7,11 +7,6 @@
 # Author: Leonardo de Moura (leonardo)
 ############################################
 import sys
-
-if sys.version >= "3":
-    print "ERROR: python 2.x required."
-    exit(1)
-
 import os
 import glob
 import re
@@ -75,6 +70,8 @@ VER_BUILD=None
 VER_REVISION=None
 PREFIX='/usr'
 GMP=False
+VS_PAR=False
+VS_PAR_NUM=8
 
 def is_windows():
     return IS_WINDOWS
@@ -132,8 +129,7 @@ def exec_cmd(cmd):
     first = True
     for e in cmd:
         if first:
-            # Allow spaces in the executable name
-	    first = False
+            first = False
             new_cmd.append(e)
         else:
             if e != "":
@@ -164,7 +160,7 @@ def exec_compiler_cmd(cmd):
 
 def test_cxx_compiler(cc):
     if is_verbose():
-        print "Testing %s..." % cc
+        print("Testing %s..." % cc)
     t = TempFile('tst.cpp')
     t.add('#include<iostream>\nint main() { return 0; }\n')
     t.commit()
@@ -172,7 +168,7 @@ def test_cxx_compiler(cc):
 
 def test_c_compiler(cc):
     if is_verbose():
-        print "Testing %s..." % cc
+        print("Testing %s..." % cc)
     t = TempFile('tst.c')
     t.add('#include<stdio.h>\nint main() { return 0; }\n')
     t.commit()
@@ -180,7 +176,7 @@ def test_c_compiler(cc):
 
 def test_gmp(cc):
     if is_verbose():
-        print "Testing GMP..."
+        print("Testing GMP...")
     t = TempFile('tstgmp.cpp')
     t.add('#include<gmp.h>\nint main() { mpz_t t; mpz_init(t); mpz_clear(t); return 0; }\n')
     t.commit()
@@ -188,7 +184,7 @@ def test_gmp(cc):
 
 def test_openmp(cc):
     if is_verbose():
-        print "Testing OpenMP..."
+        print("Testing OpenMP...")
     t = TempFile('tstomp.cpp')
     t.add('#include<omp.h>\nint main() { return omp_in_parallel() ? 1 : 0; }\n')
     t.commit()
@@ -199,12 +195,12 @@ def check_java():
     t.add('public class Hello { public static void main(String[] args) { System.out.println("Hello, World"); }}\n')
     t.commit()
     if is_verbose():
-        print "Testing %s..." % JAVAC
+        print("Testing %s..." % JAVAC)
     r = exec_cmd([JAVAC, 'Hello.java'])
     if r != 0:
         raise MKException('Failed testing Java compiler. Set environment variable JAVAC with the path to the Java compiler')
     if is_verbose():
-        print "Testing %s..." % JAVA
+        print("Testing %s..." % JAVA)
     r = exec_cmd([JAVA, 'Hello'])
     rmf('Hello.class')
     if r != 0:
@@ -222,11 +218,11 @@ def find_java_home():
     global JAVA_HOME
     if JAVA_HOME != None:
         if is_verbose():
-            print "Checking jni.h..."
+            print("Checking jni.h...")
         if os.path.exists(os.path.join(JAVA_HOME, 'include', 'jni.h')):
             return
     if is_verbose():
-        print "Finding JAVA_HOME..."
+        print("Finding JAVA_HOME...")
     t = TempFile('output')
     null = open(os.devnull, 'wb')
     try: 
@@ -240,17 +236,17 @@ def find_java_home():
         m = open_pat.match(line)
         if m:
             # Remove last 3 directives from m.group(1)
-	    print m.group(1)
+            print(m.group(1))
             tmp  = m.group(1).split(os.sep)
             path = string.join(tmp[:len(tmp) - 3], os.sep)
             if is_verbose():
-                print "Checking jni.h..."
+                print("Checking jni.h...")
             jni_dir = find_jni_h(path)
             if not jni_dir:
                 raise MKException("Failed to detect jni.h at '%s'.Possible solution: set JAVA_HOME with the path to JDK." % os.path.join(path, 'include'))
             JAVA_HOME = os.path.split(jni_dir)[0]
             if is_verbose():
-                print 'JAVA_HOME=%s' % JAVA_HOME
+                print('JAVA_HOME=%s' % JAVA_HOME)
             return
     raise MKException('Failed to find JAVA_HOME')
 
@@ -259,7 +255,7 @@ def is64():
 
 def check_ar():
     if is_verbose():
-        print "Testing ar..."
+        print("Testing ar...")
     if which('ar')== None:
         raise MKException('ar (archive tool) was not found')
 
@@ -320,7 +316,7 @@ def dos2unix(fname):
         fout.close()
         shutil.move(fname_new, fname)
         if is_verbose():
-            print "dos2unix '%s'" % fname
+            print("dos2unix '%s'" % fname)
 
 def dos2unix_tree_core(pattern, dir, files):
     for filename in files:
@@ -337,7 +333,7 @@ def check_eol():
         # Linux/OSX/BSD check if the end-of-line is cr/lf
         if is_cr_lf('LICENSE.txt'):
             if is_verbose():
-                print "Fixing end of line..."
+                print("Fixing end of line...")
             dos2unix_tree()
 
 if os.name == 'nt':
@@ -353,53 +349,55 @@ elif os.name == 'posix':
         IS_LINUX=True
 
 def display_help(exit_code):
-    print "mk_make.py: Z3 Makefile generator\n"
-    print "This script generates the Makefile for the Z3 theorem prover."
-    print "It must be executed from the Z3 root directory."
-    print "\nOptions:"
-    print "  -h, --help                    display this message."
-    print "  -s, --silent                  do not print verbose messages."
+    print("mk_make.py: Z3 Makefile generator\n")
+    print("This script generates the Makefile for the Z3 theorem prover.")
+    print("It must be executed from the Z3 root directory.")
+    print("\nOptions:")
+    print("  -h, --help                    display this message.")
+    print("  -s, --silent                  do not print verbose messages.")
     if not IS_WINDOWS:
-        print "  -p <dir>, --prefix=<dir>      installation prefix (default: %s)." % PREFIX
-        print "  -y <dir>, --pydir=<dir>       installation prefix for Z3 python bindings (default: %s)." % PYTHON_PACKAGE_DIR
-    print "  -b <sudir>, --build=<subdir>  subdirectory where Z3 will be built (default: build)."
-    print "  -d, --debug                   compile Z3 in debug mode."
-    print "  -t, --trace                   enable tracing in release mode."
+        print("  -p <dir>, --prefix=<dir>      installation prefix (default: %s)." % PREFIX)
+        print("  -y <dir>, --pydir=<dir>       installation prefix for Z3 python bindings (default: %s)." % PYTHON_PACKAGE_DIR)
+    else:
+        print("  --parallel=num                use cl option /MP with 'num' parallel processes")
+    print("  -b <sudir>, --build=<subdir>  subdirectory where Z3 will be built (default: build).")
+    print("  -d, --debug                   compile Z3 in debug mode.")
+    print("  -t, --trace                   enable tracing in release mode.")
     if IS_WINDOWS:
-        print "  -x, --x64                     create 64 binary when using Visual Studio."
-    print "  -m, --makefiles               generate only makefiles."
+        print("  -x, --x64                     create 64 binary when using Visual Studio.")
+    print("  -m, --makefiles               generate only makefiles.")
     if IS_WINDOWS:
-        print "  -v, --vsproj                  generate Visual Studio Project Files."
+        print("  -v, --vsproj                  generate Visual Studio Project Files.")
     if IS_WINDOWS:
-        print "  -n, --nodotnet                do not generate Microsoft.Z3.dll make rules."
-    print "  -j, --java                    generate Java bindinds."
-    print "  --staticlib                   build Z3 static library."
+        print("  -n, --nodotnet                do not generate Microsoft.Z3.dll make rules.")
+    print("  -j, --java                    generate Java bindinds.")
+    print("  --staticlib                   build Z3 static library.")
     if not IS_WINDOWS:
-        print "  -g, --gmp                     use GMP."
-    print ""
-    print "Some influential environment variables:"
+        print("  -g, --gmp                     use GMP.")
+    print("")
+    print("Some influential environment variables:")
     if not IS_WINDOWS:
-        print "  CXX        C++ compiler"
-        print "  CC         C compiler"
-        print "  LDFLAGS    Linker flags, e.g., -L<lib dir> if you have libraries in a non-standard directory"
-        print "  CPPFLAGS   Preprocessor flags, e.g., -I<include dir> if you have header files in a non-standard directory"
-        print "  CXXFLAGS   C++ compiler flags"
-    print "  JAVA       Java virtual machine (only relevant if -j or --java option is provided)"
-    print "  JAVAC      Java compiler (only relevant if -j or --java option is provided)"
-    print "  JAVA_HOME  JDK installation directory (only relevant if -j or --java option is provided)"
+        print("  CXX        C++ compiler")
+        print("  CC         C compiler")
+        print("  LDFLAGS    Linker flags, e.g., -L<lib dir> if you have libraries in a non-standard directory")
+        print("  CPPFLAGS   Preprocessor flags, e.g., -I<include dir> if you have header files in a non-standard directory")
+        print("  CXXFLAGS   C++ compiler flags")
+    print("  JAVA       Java virtual machine (only relevant if -j or --java option is provided)")
+    print("  JAVAC      Java compiler (only relevant if -j or --java option is provided)")
+    print("  JAVA_HOME  JDK installation directory (only relevant if -j or --java option is provided)")
     exit(exit_code)
 
 # Parse configuration option for mk_make script
 def parse_options():
-    global VERBOSE, DEBUG_MODE, IS_WINDOWS, VS_X64, ONLY_MAKEFILES, SHOW_CPPS, VS_PROJ, TRACE
+    global VERBOSE, DEBUG_MODE, IS_WINDOWS, VS_X64, ONLY_MAKEFILES, SHOW_CPPS, VS_PROJ, TRACE, VS_PAR, VS_PAR_NUM
     global DOTNET_ENABLED, JAVA_ENABLED, STATIC_LIB, PREFIX, GMP, PYTHON_PACKAGE_DIR
     try:
         options, remainder = getopt.gnu_getopt(sys.argv[1:], 
                                                'b:dsxhmcvtnp:gjy:', 
                                                ['build=', 'debug', 'silent', 'x64', 'help', 'makefiles', 'showcpp', 'vsproj',
-                                                'trace', 'nodotnet', 'staticlib', 'prefix=', 'gmp', 'java', 'pydir='])
+                                                'trace', 'nodotnet', 'staticlib', 'prefix=', 'gmp', 'java', 'pydir=', 'parallel='])
     except:
-        print "ERROR: Invalid command line option"
+        print("ERROR: Invalid command line option")
         display_help(1)
 
     for opt, arg in options:
@@ -429,8 +427,11 @@ def parse_options():
             DOTNET_ENABLED = False
         elif opt in ('--staticlib'):
             STATIC_LIB = True
-        elif opt in ('-p', '--prefix'):
+        elif not IS_WINDOWS and opt in ('-p', '--prefix'):
             PREFIX = arg
+        elif IS_WINDOWS and opt == '--parallel':
+            VS_PAR = True
+            VS_PAR_NUM = int(arg)
         elif opt in ('-y', '--pydir'):
             PYTHON_PACKAGE_DIR = arg
             mk_dir(PYTHON_PACKAGE_DIR)
@@ -439,7 +440,7 @@ def parse_options():
         elif opt in ('-j', '--java'):
             JAVA_ENABLED = True
         else:
-            print "ERROR: Invalid command line option '%s'" % opt
+            print("ERROR: Invalid command line option '%s'" % opt)
             display_help(1)
 
 # Return a list containing a file names included using '#include' in
@@ -490,7 +491,7 @@ def set_z3py_dir(p):
         raise MKException("Python bindings directory '%s' does not exist" % full)
     Z3PY_SRC_DIR = full
     if VERBOSE:
-        print "Python bindinds directory was detected."
+        print("Python bindinds directory was detected.")
 
 _UNIQ_ID = 0
 
@@ -656,8 +657,32 @@ class Component:
             out.write(' -I%s' % get_component(dep).to_src_dir)
         out.write('\n')
         mk_dir(os.path.join(BUILD_DIR, self.build_dir))
-        for cppfile in get_cpp_files(self.src_dir):
-            self.add_cpp_rules(out, include_defs, cppfile)
+        if VS_PAR and IS_WINDOWS:
+            cppfiles = get_cpp_files(self.src_dir)
+            dependencies = set()
+            for cppfile in cppfiles:
+                dependencies.add(os.path.join(self.to_src_dir, cppfile))
+                self.add_rule_for_each_include(out, cppfile)
+                includes = extract_c_includes(os.path.join(self.src_dir, cppfile))
+                for include in includes:
+                    owner = self.find_file(include, cppfile)
+                    dependencies.add('%s.node' % os.path.join(owner.build_dir, include))
+            for cppfile in cppfiles:
+                out.write('%s$(OBJ_EXT) ' % os.path.join(self.build_dir, os.path.splitext(cppfile)[0]))
+            out.write(': ')
+            for dep in dependencies:
+                out.write(dep)
+                out.write(' ')
+            out.write('\n')
+            out.write('\t@$(CXX) $(CXXFLAGS) /MP%s $(%s)' % (VS_PAR_NUM, include_defs))
+            for cppfile in cppfiles:
+                out.write(' ')
+                out.write(os.path.join(self.to_src_dir, cppfile))
+            out.write('\n')
+            out.write('\tmove *.obj %s\n' % self.build_dir)
+        else:
+            for cppfile in get_cpp_files(self.src_dir):
+                self.add_cpp_rules(out, include_defs, cppfile)
 
     # Return true if the component should be included in the all: rule
     def main_component(self):
@@ -750,7 +775,7 @@ def comp_components(c1, c2):
 
 # Sort components based on (reverse) definition time
 def sort_components(cnames):
-    return sorted(cnames, cmp=comp_components)
+    return sorted(cnames, key=lambda c: get_component(c).id, reverse=True)
 
 class ExeComponent(Component):
     def __init__(self, name, exe_name, path, deps, install):
@@ -933,10 +958,8 @@ class DLLComponent(Component):
             mk_dir(os.path.join(dist_path, 'bin'))
             shutil.copy('%s.dll' % os.path.join(build_path, self.dll_name),
                         '%s.dll' % os.path.join(dist_path, 'bin', self.dll_name))
-            if self.static:
-                mk_dir(os.path.join(dist_path, 'bin'))
-                shutil.copy('%s.lib' % os.path.join(build_path, self.dll_name),
-                            '%s.lib' % os.path.join(dist_path, 'bin', self.dll_name))
+            shutil.copy('%s.lib' % os.path.join(build_path, self.dll_name),
+                        '%s.lib' % os.path.join(dist_path, 'bin', self.dll_name))
 
 class DotNetDLLComponent(Component):
     def __init__(self, name, dll_name, path, deps, assembly_info_dir):
@@ -1042,6 +1065,11 @@ class JavaDLLComponent(Component):
     def main_component(self):
         return is_java_enabled()
 
+    def mk_win_dist(self, build_path, dist_path):
+        if JAVA_ENABLED:
+            mk_dir(os.path.join(dist_path, 'bin'))
+            shutil.copy('%s.jar' % os.path.join(build_path, self.package_name),
+                        '%s.jar' % os.path.join(dist_path, 'bin', self.package_name))
 
 class ExampleComponent(Component):
     def __init__(self, name, path):
@@ -1162,7 +1190,7 @@ class PythonExampleComponent(ExampleComponent):
         for py in filter(lambda f: f.endswith('.py'), os.listdir(full)):
             shutil.copyfile(os.path.join(full, py), os.path.join(BUILD_DIR, py))
             if is_verbose():
-                print "Copied Z3Py example '%s' to '%s'" % (py, BUILD_DIR)
+                print("Copied Z3Py example '%s' to '%s'" % (py, BUILD_DIR))
         out.write('_ex_%s: \n\n' % self.name)
 
 
@@ -1174,7 +1202,7 @@ def reg_component(name, c):
     _ComponentNames.add(name)
     _Name2Component[name] = c
     if VERBOSE:
-        print "New component: '%s'" % name
+        print("New component: '%s'" % name)
 
 def add_lib(name, deps=[], path=None, includes2install=[]):
     c = LibComponent(name, path, deps, includes2install)
@@ -1250,12 +1278,12 @@ def mk_config():
                 'SLINK_FLAGS=/nologo /LDd\n')
             if not VS_X64:
                 config.write(
-                    'CXXFLAGS=/c /Zi /nologo /openmp /W3 /WX- /Od /Oy- /D WIN32 /D _DEBUG /D Z3DEBUG /D _CONSOLE /D _TRACE /D _WINDOWS /Gm /EHsc /RTC1 /MDd /GS /fp:precise /Zc:wchar_t /Zc:forScope /Gd /analyze- /arch:SSE2\n'
+                    'CXXFLAGS=/c /Zi /nologo /openmp /W3 /WX- /Od /Oy- /D WIN32 /D _DEBUG /D Z3DEBUG /D _CONSOLE /D _TRACE /D _WINDOWS /Gm- /EHsc /RTC1 /MDd /GS /fp:precise /Zc:wchar_t /Zc:forScope /Gd /analyze- /arch:SSE2\n'
                     'LINK_EXTRA_FLAGS=/link /DEBUG /MACHINE:X86 /SUBSYSTEM:CONSOLE /INCREMENTAL:NO /STACK:8388608 /OPT:REF /OPT:ICF /TLBID:1 /DYNAMICBASE /NXCOMPAT\n'
                     'SLINK_EXTRA_FLAGS=/link /DEBUG /MACHINE:X86 /SUBSYSTEM:WINDOWS /INCREMENTAL:NO /STACK:8388608 /OPT:REF /OPT:ICF /TLBID:1 /DYNAMICBASE:NO\n')
             else:
                 config.write(
-                    'CXXFLAGS=/c /Zi /nologo /openmp /W3 /WX- /Od /Oy- /D WIN32 /D _AMD64_ /D _DEBUG /D Z3DEBUG /D _CONSOLE /D _TRACE /D _WINDOWS /Gm /EHsc /RTC1 /MDd /GS /fp:precise /Zc:wchar_t /Zc:forScope /Gd /analyze-\n'
+                    'CXXFLAGS=/c /Zi /nologo /openmp /W3 /WX- /Od /Oy- /D WIN32 /D _AMD64_ /D _DEBUG /D Z3DEBUG /D _CONSOLE /D _TRACE /D _WINDOWS /Gm- /EHsc /RTC1 /MDd /GS /fp:precise /Zc:wchar_t /Zc:forScope /Gd /analyze-\n'
                     'LINK_EXTRA_FLAGS=/link /DEBUG /MACHINE:X64 /SUBSYSTEM:CONSOLE /INCREMENTAL:NO /STACK:8388608 /OPT:REF /OPT:ICF /TLBID:1 /DYNAMICBASE /NXCOMPAT\n'
                     'SLINK_EXTRA_FLAGS=/link /DEBUG /MACHINE:X64 /SUBSYSTEM:WINDOWS /INCREMENTAL:NO /STACK:8388608 /OPT:REF /OPT:ICF /TLBID:1 /DYNAMICBASE:NO\n')
         else:
@@ -1281,11 +1309,11 @@ def mk_config():
 
         # End of Windows VS config.mk
         if is_verbose():
-            print '64-bit:         %s' % is64()
+            print('64-bit:         %s' % is64())
             if is_java_enabled():
-                print 'Java Home:      %s' % JAVA_HOME
-                print 'Java Compiler:  %s' % JAVAC
-                print 'Java VM:        %s' % JAVA
+                print('Java Home:      %s' % JAVA_HOME)
+                print('Java Compiler:  %s' % JAVAC)
+                print('Java VM:        %s' % JAVA)
     else:
         global CXX, CC, GMP, CPPFLAGS, CXXFLAGS, LDFLAGS
         ARITH = "internal"
@@ -1367,17 +1395,17 @@ def mk_config():
         config.write('SLINK_EXTRA_FLAGS=%s\n' % SLIBEXTRAFLAGS)
         config.write('SLINK_OUT_FLAG=-o \n')
         if is_verbose():
-            print 'Host platform:  %s' % sysname
-            print 'C++ Compiler:   %s' % CXX
-            print 'C Compiler  :   %s' % CC
-            print 'Arithmetic:     %s' % ARITH
-            print 'OpenMP:         %s' % HAS_OMP
-            print 'Prefix:         %s' % PREFIX
-            print '64-bit:         %s' % is64()
+            print('Host platform:  %s' % sysname)
+            print('C++ Compiler:   %s' % CXX)
+            print('C Compiler  :   %s' % CC)
+            print('Arithmetic:     %s' % ARITH)
+            print('OpenMP:         %s' % HAS_OMP)
+            print('Prefix:         %s' % PREFIX)
+            print('64-bit:         %s' % is64())
             if is_java_enabled():
-                print 'Java Home:      %s' % JAVA_HOME
-                print 'Java Compiler:  %s' % JAVAC
-                print 'Java VM:        %s' % JAVA
+                print('Java Home:      %s' % JAVA_HOME)
+                print('Java Compiler:  %s' % JAVAC)
+                print('Java VM:        %s' % JAVA)
 
 def mk_install(out):
     out.write('install:\n')
@@ -1403,7 +1431,7 @@ def mk_makefile():
     mk_dir(BUILD_DIR)
     mk_config()
     if VERBOSE:
-        print "Writing %s" % os.path.join(BUILD_DIR, 'Makefile')
+        print("Writing %s" % os.path.join(BUILD_DIR, 'Makefile'))
     out = open(os.path.join(BUILD_DIR, 'Makefile'), 'w')
     out.write('# Automatically generated file.\n')
     out.write('include config.mk\n')
@@ -1431,24 +1459,24 @@ def mk_makefile():
         mk_uninstall(out)
     # Finalize
     if VERBOSE:
-        print "Makefile was successfully generated."
+        print("Makefile was successfully generated.")
         if not IS_WINDOWS:
-            print "  python packages dir:", PYTHON_PACKAGE_DIR
+            print("  python packages dir: %s" % PYTHON_PACKAGE_DIR)
         if DEBUG_MODE:
-            print "  compilation mode: Debug"
+            print("  compilation mode: Debug")
         else:
-            print "  compilation mode: Release"
+            print("  compilation mode: Release")
         if IS_WINDOWS:
             if VS_X64:
-                print "  platform: x64\n"
-                print "To build Z3, open a [Visual Studio x64 Command Prompt], then"
+                print("  platform: x64\n")
+                print("To build Z3, open a [Visual Studio x64 Command Prompt], then")
             else:
-                print "  platform: x86"
-                print "To build Z3, open a [Visual Studio Command Prompt], then"
-            print "type 'cd %s && nmake'\n" % os.path.join(os.getcwd(), BUILD_DIR)
-            print 'Remark: to open a Visual Studio Command Prompt, go to: "Start > All Programs > Visual Studio > Visual Studio Tools"'
+                print("  platform: x86")
+                print("To build Z3, open a [Visual Studio Command Prompt], then")
+            print("type 'cd %s && nmake'\n" % os.path.join(os.getcwd(), BUILD_DIR))
+            print('Remark: to open a Visual Studio Command Prompt, go to: "Start > All Programs > Visual Studio > Visual Studio Tools"')
         else:
-            print "Type 'cd %s; make' to build Z3" % BUILD_DIR
+            print("Type 'cd %s; make' to build Z3" % BUILD_DIR)
         
 # Generate automatically generated source code
 def mk_auto_src():
@@ -1543,7 +1571,7 @@ def def_module_params(module_name, export, params, class_name=None, description=
     out.write('};\n')
     out.write('#endif\n')
     if is_verbose():
-        print "Generated '%s'" % hpp
+        print("Generated '%s'" % hpp)
 
 def max_memory_param():
     return ('max_memory', UINT, UINT_MAX, 'maximum amount of memory in megabytes')
@@ -1557,6 +1585,10 @@ PYG_GLOBALS = { 'UINT' : UINT, 'BOOL' : BOOL, 'DOUBLE' : DOUBLE, 'STRING' : STRI
                 'max_steps_param' : max_steps_param,
                 'def_module_params' : def_module_params }
 
+def _execfile(file, globals=globals(), locals=locals()):
+    with open(file, "r") as fh:
+        exec(fh.read()+"\n", globals, locals)
+
 # Execute python auxiliary scripts that generate extra code for Z3.
 def exec_pyg_scripts():
     global CURR_PYG
@@ -1565,7 +1597,7 @@ def exec_pyg_scripts():
             if f.endswith('.pyg'):
                 script = os.path.join(root, f)
                 CURR_PYG = script
-                execfile(script, PYG_GLOBALS)
+                _execfile(script, PYG_GLOBALS)
 
 # TODO: delete after src/ast/pattern/expr_pattern_match
 # database.smt ==> database.h
@@ -1578,7 +1610,7 @@ def mk_pat_db():
         fout.write('"%s\\n"\n' % line.strip('\n'))
     fout.write(';\n')    
     if VERBOSE:
-        print "Generated '%s'" % os.path.join(c.src_dir, 'database.h')
+        print("Generated '%s'" % os.path.join(c.src_dir, 'database.h'))
 
 # Update version numbers
 def update_version():
@@ -1603,7 +1635,7 @@ def mk_version_dot_h(major, minor, build, revision):
     fout.write('#define Z3_BUILD_NUMBER    %s\n' % build)
     fout.write('#define Z3_REVISION_NUMBER %s\n' % revision)
     if VERBOSE:
-        print "Generated '%s'" % os.path.join(c.src_dir, 'version.h')
+        print("Generated '%s'" % os.path.join(c.src_dir, 'version.h'))
 
 # Update version number in AssemblyInfo.cs files
 def update_all_assembly_infos(major, minor, build, revision):
@@ -1652,13 +1684,13 @@ def update_assembly_info_version(assemblyinfo, major, minor, build, revision, is
         else:
             fout.write(line)
     # if VERBOSE:
-    #    print "%s version numbers updated at '%s'" % (num_updates, assemblyinfo)
+    #    print("%s version numbers updated at '%s'" % (num_updates, assemblyinfo))
     assert num_updates == 2, "unexpected number of version number updates"
     fin.close()
     fout.close()
     shutil.move(tmp, assemblyinfo)
     if VERBOSE:
-        print "Updated '%s'" % assemblyinfo
+        print("Updated '%s'" % assemblyinfo)
 
 ADD_TACTIC_DATA=[]
 ADD_PROBE_DATA=[]
@@ -1700,7 +1732,7 @@ def mk_install_tactic_cpp(cnames, path):
                         added_include = True
                         fout.write('#include"%s"\n' % h_file)
                     try: 
-                        exec line.strip('\n ') in globals()
+                        exec(line.strip('\n '), globals())
                     except:
                         raise MKException("Failed processing ADD_TACTIC command at '%s'\n%s" % (fullname, line))
                 if probe_pat.match(line):
@@ -1708,7 +1740,7 @@ def mk_install_tactic_cpp(cnames, path):
                         added_include = True
                         fout.write('#include"%s"\n' % h_file)
                     try: 
-                        exec line.strip('\n ') in globals()
+                        exec(line.strip('\n '), globals())
                     except:
                         raise MKException("Failed processing ADD_PROBE command at '%s'\n%s" % (fullname, line))
     # First pass will just generate the tactic factories
@@ -1727,7 +1759,7 @@ def mk_install_tactic_cpp(cnames, path):
         fout.write('  ADD_PROBE("%s", "%s", %s);\n' % data)
     fout.write('}\n')
     if VERBOSE:
-        print "Generated '%s'" % fullname
+        print("Generated '%s'" % fullname)
 
 def mk_all_install_tactic_cpps():
     if not ONLY_MAKEFILES:
@@ -1790,7 +1822,7 @@ def mk_mem_initializer_cpp(cnames, path):
         fout.write('\n')
     fout.write('}\n')
     if VERBOSE:
-        print "Generated '%s'" % fullname
+        print("Generated '%s'" % fullname)
 
 def mk_all_mem_initializer_cpps():
     if not ONLY_MAKEFILES:
@@ -1847,7 +1879,7 @@ def mk_gparams_register_modules(cnames, path):
         fout.write('gparams::register_module_descr("%s", "%s");\n' % (mod, descr))
     fout.write('}\n')
     if VERBOSE:
-        print "Generated '%s'" % fullname
+        print("Generated '%s'" % fullname)
 
 def mk_all_gparams_register_modules():
     if not ONLY_MAKEFILES:
@@ -1880,7 +1912,7 @@ def mk_def_file(c):
                     i = i + 1
                 num = num + 1
     if VERBOSE:
-        print "Generated '%s'" % defname
+        print("Generated '%s'" % defname)
 
 def mk_def_files():
     if not ONLY_MAKEFILES:
@@ -1900,7 +1932,7 @@ def cp_z3pyc_to_build():
         shutil.copyfile(os.path.join(Z3PY_SRC_DIR, pyc), os.path.join(BUILD_DIR, pyc))
         os.remove(os.path.join(Z3PY_SRC_DIR, pyc))
         if is_verbose():
-            print "Generated '%s'" % pyc
+            print("Generated '%s'" % pyc)
 
 def mk_bindings(api_files):
     if not ONLY_MAKEFILES:
@@ -1911,12 +1943,12 @@ def mk_bindings(api_files):
         for api_file in api_files:
             api_file_path = api.find_file(api_file, api.name)
             new_api_files.append(os.path.join(api_file_path.src_dir, api_file))
-        g = {}
+        g = globals()
         g["API_FILES"] = new_api_files
         if is_java_enabled():
             check_java()
             mk_z3consts_java(api_files)
-        execfile(os.path.join('scripts', 'update_api.py'), g) # HACK
+        _execfile(os.path.join('scripts', 'update_api.py'), g) # HACK
         cp_z3pyc_to_build()
                           
 # Extract enumeration types from API files, and add python definitions.
@@ -1980,7 +2012,8 @@ def mk_z3consts_py(api_files):
                 if m:
                     name = words[1]
                     z3consts.write('# enum %s\n' % name)
-                    for k, i in decls.iteritems():
+                    for k in decls:
+                        i = decls[k]
                         z3consts.write('%s = %s\n' % (k, i))
                     z3consts.write('\n')
                     mode = SEARCHING
@@ -1994,7 +2027,7 @@ def mk_z3consts_py(api_files):
                     idx = idx + 1
             linenum = linenum + 1
     if VERBOSE:
-        print "Generated '%s'" % os.path.join(Z3PY_SRC_DIR, 'z3consts.py')
+        print("Generated '%s'" % os.path.join(Z3PY_SRC_DIR, 'z3consts.py'))
                 
 
 # Extract enumeration types from z3_api.h, and add .Net definitions
@@ -2064,7 +2097,8 @@ def mk_z3consts_dotnet(api_files):
                         z3consts.write('  /// <summary>%s</summary>\n' % name)
                         z3consts.write('  public enum %s {\n' % name)
                         z3consts.write
-                        for k, i in decls.iteritems():
+                        for k in decls:
+                            i = decls[k]
                             z3consts.write('  %s = %s,\n' % (k, i))
                         z3consts.write('  }\n\n')
                     mode = SEARCHING
@@ -2079,7 +2113,7 @@ def mk_z3consts_dotnet(api_files):
             linenum = linenum + 1
     z3consts.write('}\n');
     if VERBOSE:
-        print "Generated '%s'" % os.path.join(dotnet.src_dir, 'Enumerations.cs')
+        print("Generated '%s'" % os.path.join(dotnet.src_dir, 'Enumerations.cs'))
 
 
 # Extract enumeration types from z3_api.h, and add Java definitions
@@ -2153,7 +2187,8 @@ def mk_z3consts_java(api_files):
                         efile.write('public enum %s {\n' % name)
                         efile.write
                         first = True
-                        for k, i in decls.iteritems():
+                        for k in decls:
+                            i = decls[k]
                             if first:
                                first = False 
                             else:
@@ -2184,7 +2219,7 @@ def mk_z3consts_java(api_files):
                     idx = idx + 1
             linenum = linenum + 1
     if VERBOSE:
-        print "Generated '%s'" % ('%s' % gendir)
+        print("Generated '%s'" % ('%s' % gendir))
 
 def mk_gui_str(id):
     return '4D2F40D8-E5F9-473B-B548-%012d' % id
@@ -2271,7 +2306,7 @@ def mk_vs_proj(name, components):
     f.write('  </ImportGroup>\n')
     f.write('</Project>\n')
     if is_verbose():
-        print "Generated '%s'" % proj_name
+        print("Generated '%s'" % proj_name)
 
 def mk_win_dist(build_path, dist_path):
     for c in get_components():
diff --git a/scripts/mk_win_dist.py b/scripts/mk_win_dist.py
index 57ae66b03..dd50a3977 100644
--- a/scripts/mk_win_dist.py
+++ b/scripts/mk_win_dist.py
@@ -16,13 +16,15 @@ import subprocess
 import zipfile
 from mk_exception import *
 from mk_project import *
+import mk_util
 
 BUILD_DIR='build-dist'
-BUILD_X64_DIR='build-dist/x64'
-BUILD_X86_DIR='build-dist/x86'
+BUILD_X64_DIR=os.path.join('build-dist', 'x64')
+BUILD_X86_DIR=os.path.join('build-dist', 'x86')
 VERBOSE=True
 DIST_DIR='dist'
 FORCE_MK=False
+JAVA_ENABLED=True
 
 def set_verbose(flag):
     global VERBOSE
@@ -38,8 +40,8 @@ def mk_dir(d):
 def set_build_dir(path):
     global BUILD_DIR
     BUILD_DIR = path
-    BUILD_X86_DIR = '%s/x86' % path
-    BUILD_X64_DIR = '%s/x64' % path
+    BUILD_X86_DIR = os.path.join(path, 'x86')
+    BUILD_X64_DIR = os.path.join(path, 'x64')
     mk_dir(BUILD_X86_DIR)
     mk_dir(BUILD_X64_DIR)
 
@@ -52,16 +54,18 @@ def display_help():
     print "  -s, --silent                  do not print verbose messages."
     print "  -b <sudir>, --build=<subdir>  subdirectory where x86 and x64 Z3 versions will be built (default: build-dist)."
     print "  -f, --force                   force script to regenerate Makefiles."
+    print "  --nojava                      do not include Java bindings in the binary distribution files."
     exit(0)
 
 # Parse configuration option for mk_make script
 def parse_options():
-    global FORCE_MK
+    global FORCE_MK, JAVA_ENABLED
     path = BUILD_DIR
     options, remainder = getopt.gnu_getopt(sys.argv[1:], 'b:hsf', ['build=', 
                                                                    'help',
                                                                    'silent',
-                                                                   'force'
+                                                                   'force',
+                                                                   'nojava'
                                                                    ])
     for opt, arg in options:
         if opt in ('-b', '--build'):
@@ -74,18 +78,22 @@ def parse_options():
             display_help()
         elif opt in ('-f', '--force'):
             FORCE_MK = True
+        elif opt == '--nojava':
+            JAVA_ENABLED = False
         else:
             raise MKException("Invalid command line option '%s'" % opt)
     set_build_dir(path)
 
 # Check whether build directory already exists or not
 def check_build_dir(path):
-    return os.path.exists(path) and os.path.exists('%s/Makefile' % path)
+    return os.path.exists(path) and os.path.exists(os.path.join(path, 'Makefile'))
 
 # Create a build directory using mk_make.py
 def mk_build_dir(path, x64):
     if not check_build_dir(path) or FORCE_MK:
-        opts = ["python", "scripts/mk_make.py", "-b", path]
+        opts = ["python", os.path.join('scripts', 'mk_make.py'), "-b", path]
+        if JAVA_ENABLED:
+            opts.append('--java')
         if x64:
             opts.append('-x')
         if subprocess.call(opts) != 0:
@@ -147,8 +155,12 @@ def mk_dist_dir_core(x64):
     else:
         platform = "x86"
         build_path = BUILD_X86_DIR
-    dist_path = '%s/z3-%s.%s.%s-%s' % (DIST_DIR, major, minor, build, platform)
+    dist_path = os.path.join(DIST_DIR, 'z3-%s.%s.%s-%s' % (major, minor, build, platform))
     mk_dir(dist_path)
+    if JAVA_ENABLED:
+        # HACK: Propagate JAVA_ENABLED flag to mk_util
+        # TODO: fix this hack
+        mk_util.JAVA_ENABLED = JAVA_ENABLED
     mk_win_dist(build_path, dist_path)
     if is_verbose():
         print "Generated %s distribution folder at '%s'" % (platform, dist_path)
@@ -225,7 +237,7 @@ def cp_vs_runtime_core(x64):
     path  = '%sredist\\%s' % (vcdir, platform)
     VS_RUNTIME_FILES = []
     os.path.walk(path, cp_vs_runtime_visitor, '*.dll')
-    bin_dist_path = '%s/%s/bin' % (DIST_DIR, get_dist_path(x64))
+    bin_dist_path = os.path.join(DIST_DIR, get_dist_path(x64), 'bin')
     for f in VS_RUNTIME_FILES:
         shutil.copy(f, bin_dist_path)
         if is_verbose():
@@ -236,8 +248,8 @@ def cp_vs_runtime():
     cp_vs_runtime_core(False)
 
 def cp_license():
-    shutil.copy("LICENSE.txt", "%s/%s" % (DIST_DIR, get_dist_path(True)))
-    shutil.copy("LICENSE.txt", "%s/%s" % (DIST_DIR, get_dist_path(False)))
+    shutil.copy("LICENSE.txt", os.path.join(DIST_DIR, get_dist_path(True)))
+    shutil.copy("LICENSE.txt", os.path.join(DIST_DIR, get_dist_path(False)))
 
 # Entry point
 def main():
diff --git a/scripts/trackall.sh b/scripts/trackall.sh
new file mode 100755
index 000000000..d8351af24
--- /dev/null
+++ b/scripts/trackall.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# Script for "cloning" (and tracking) all branches at codeplex.
+# On Windows, this script must be executed in the "git Bash" console.
+for branch in `git branch -a | grep remotes | grep -v HEAD | grep -v master`; do
+    git branch --track ${branch##*/} $branch
+done
+git fetch --all
+git pull --all
diff --git a/scripts/update_api.py b/scripts/update_api.py
index a636a1a02..08dd012e3 100644
--- a/scripts/update_api.py
+++ b/scripts/update_api.py
@@ -84,6 +84,19 @@ def lib():
         raise Z3Exception("init(Z3_LIBRARY_PATH) must be invoked before using Z3-python")
   return _lib
 
+def _to_ascii(s):
+  if isinstance(s, str):
+    return s.encode('ascii')
+  else:
+    return s
+
+if sys.version < '3':
+  def _to_pystr(s):
+     return s
+else:
+  def _to_pystr(s):
+     return s.decode('utf-8')
+
 def init(PATH):
   global _lib
   _lib = ctypes.CDLL(PATH)
@@ -146,20 +159,22 @@ next_type_id = FIRST_OBJ_ID
 
 def def_Type(var, c_type, py_type):
     global next_type_id
-    exec ('%s = %s' % (var, next_type_id)) in globals()
+    exec('%s = %s' % (var, next_type_id), globals())
     Type2Str[next_type_id]   = c_type
     Type2PyStr[next_type_id] = py_type
     next_type_id    = next_type_id + 1
 
 def def_Types():
-    pat1 = re.compile(" *def_Type.*")
+    import re
+    pat1 = re.compile(" *def_Type\(\'(.*)\',[^\']*\'(.*)\',[^\']*\'(.*)\'\)[ \t]*")
     for api_file in API_FILES:
         api = open(api_file, 'r')
         for line in api:
             m = pat1.match(line)
             if m:
-                eval(line)
-    for k, v in Type2Str.iteritems():
+                def_Type(m.group(1), m.group(2), m.group(3))
+    for k in Type2Str:
+        v = Type2Str[k]
         if is_obj(k):
             Type2Dotnet[k] = v
 
@@ -258,7 +273,7 @@ def param2java(p):
         elif param_type(p) == STRING:
             return "StringPtr"
         else:
-            print "ERROR: unreachable code"
+            print("ERROR: unreachable code")
             assert(False)
             exit(1)
     if k == IN_ARRAY or k == INOUT_ARRAY or k == OUT_ARRAY:
@@ -313,6 +328,17 @@ def display_args(num):
             core_py.write(", ")
         core_py.write("a%s" % i)
 
+def display_args_to_z3(params):
+    i = 0
+    for p in params:
+        if i > 0:
+            core_py.write(", ")
+        if param_type(p) == STRING:
+            core_py.write("_to_ascii(a%s)" % i)
+        else:
+            core_py.write("a%s" % i)
+        i = i + 1
+
 def mk_py_wrappers():
     core_py.write("\n")
     for sig in _API2PY:
@@ -327,13 +353,15 @@ def mk_py_wrappers():
             core_py.write("  r = lib().%s(" % name)
         else:
             core_py.write("  lib().%s(" % name)
-        display_args(num)
+        display_args_to_z3(params)
         core_py.write(")\n")
         if len(params) > 0 and param_type(params[0]) == CONTEXT:
             core_py.write("  err = lib().Z3_get_error_code(a0)\n")
             core_py.write("  if err != Z3_OK:\n")
             core_py.write("    raise Z3Exception(lib().Z3_get_error_msg_ex(a0, err))\n")
-        if result != VOID:
+        if result == STRING:
+            core_py.write("  return _to_pystr(r)\n")
+        elif result != VOID:
             core_py.write("  return r\n")
         core_py.write("\n")
 
@@ -356,7 +384,8 @@ def mk_dotnet():
     dotnet.write('#pragma warning disable 1591\n\n');
     dotnet.write('namespace Microsoft.Z3\n')
     dotnet.write('{\n')
-    for k, v in Type2Str.iteritems():
+    for k in Type2Str:
+        v = Type2Str[k]
         if is_obj(k):
             dotnet.write('    using %s = System.IntPtr;\n' % v)
     dotnet.write('\n');
@@ -579,7 +608,7 @@ def mk_java():
     java_wrapper.write('  }                                                                    \n\n')
     java_wrapper.write('#define RELEASELONGAELEMS(OLD,NEW)                                   \\\n')
     java_wrapper.write('  delete [] NEW;                                                     \n\n')
-    java_wrapper.write('#define GETLONGAREGION(T,OLD,Z,SZ,NEW)				    \\\n')
+    java_wrapper.write('#define GETLONGAREGION(T,OLD,Z,SZ,NEW)                              \\\n')
     java_wrapper.write('  {                                                                 \\\n')
     java_wrapper.write('    jlong * temp = new jlong[SZ];                                   \\\n')
     java_wrapper.write('    jenv->GetLongArrayRegion(OLD,Z,(jsize)SZ,(jlong*)temp);         \\\n')
@@ -702,7 +731,7 @@ def mk_java():
     java_wrapper.write('}\n')
     java_wrapper.write('#endif\n')
     if is_verbose():
-        print "Generated '%s'" % java_nativef
+        print("Generated '%s'" % java_nativef)
 
 def mk_log_header(file, name, params):
     file.write("void log_%s(" % name)
@@ -710,7 +739,7 @@ def mk_log_header(file, name, params):
     for p in params:
         if i > 0:
             file.write(", ");
-	file.write("%s a%s" % (param2str(p), i))
+        file.write("%s a%s" % (param2str(p), i))
         i = i + 1
     file.write(")");
 
@@ -981,8 +1010,8 @@ exe_c.close()
 core_py.close()
 
 if is_verbose():
-    print "Generated '%s'" % os.path.join(api_dir, 'api_log_macros.h')
-    print "Generated '%s'" % os.path.join(api_dir, 'api_log_macros.cpp')
-    print "Generated '%s'" % os.path.join(api_dir, 'api_commands.cpp')
-    print "Generated '%s'" % os.path.join(get_z3py_dir(), 'z3core.py')
-    print "Generated '%s'" % os.path.join(dotnet_dir, 'Native.cs')
+    print("Generated '%s'" % os.path.join(api_dir, 'api_log_macros.h'))
+    print("Generated '%s'" % os.path.join(api_dir, 'api_log_macros.cpp'))
+    print("Generated '%s'" % os.path.join(api_dir, 'api_commands.cpp'))
+    print("Generated '%s'" % os.path.join(get_z3py_dir(), 'z3core.py'))
+    print("Generated '%s'" % os.path.join(dotnet_dir, 'Native.cs'))
diff --git a/src/api/api_context.cpp b/src/api/api_context.cpp
index 7dc8d1a12..9ebc771f0 100644
--- a/src/api/api_context.cpp
+++ b/src/api/api_context.cpp
@@ -106,11 +106,11 @@ namespace api {
         m_error_handler = &default_error_handler;
 
         m_basic_fid = m().get_basic_family_id();
-        m_arith_fid = m().get_family_id("arith");
-        m_bv_fid    = m().get_family_id("bv");
-        m_array_fid = m().get_family_id("array");
-        m_dt_fid    = m().get_family_id("datatype");
-        m_datalog_fid = m().get_family_id("datalog_relation");
+        m_arith_fid = m().mk_family_id("arith");
+        m_bv_fid    = m().mk_family_id("bv");
+        m_array_fid = m().mk_family_id("array");
+        m_dt_fid    = m().mk_family_id("datatype");
+        m_datalog_fid = m().mk_family_id("datalog_relation");
         m_dt_plugin = static_cast<datatype_decl_plugin*>(m().get_plugin(m_dt_fid));
 
         if (!m_user_ref_count) {
diff --git a/src/api/api_datalog.h b/src/api/api_datalog.h
index 1dc0a9cbd..51dbb72ec 100644
--- a/src/api/api_datalog.h
+++ b/src/api/api_datalog.h
@@ -55,6 +55,7 @@ namespace api {
         std::string get_last_status();
         std::string to_string(unsigned num_queries, expr*const* queries);
         void cancel() { m_context.cancel(); }
+        void reset_cancel() { m_context.reset_cancel(); }
 
         unsigned get_num_levels(func_decl* pred);
         expr_ref get_cover_delta(int level, func_decl* pred);
diff --git a/src/api/api_parsers.cpp b/src/api/api_parsers.cpp
index 69ca1fc81..8f6eb1125 100644
--- a/src/api/api_parsers.cpp
+++ b/src/api/api_parsers.cpp
@@ -252,42 +252,6 @@ extern "C" {
     // ---------------
     // Support for SMTLIB2
 
-    class z3_context_solver : public solver_na2as {
-        api::context & m_ctx;
-        smt::kernel & ctx() const { return m_ctx.get_smt_kernel(); }
-    public:
-        virtual ~z3_context_solver() {}
-        z3_context_solver(api::context& c) : m_ctx(c) {}
-        virtual void init_core(ast_manager & m, symbol const & logic) {}
-        virtual void collect_statistics(statistics & st) const {}
-        virtual void reset_core() { ctx().reset(); }
-        virtual void assert_expr(expr * t) { ctx().assert_expr(t); }
-        virtual void push_core() { ctx().push(); }
-        virtual void pop_core(unsigned n) { ctx().pop(n); }
-        virtual lbool check_sat_core(unsigned num_assumptions, expr * const * assumptions) {
-            return ctx().check(num_assumptions, assumptions);
-        }
-        virtual void get_unsat_core(ptr_vector<expr> & r) {
-            unsigned sz = ctx().get_unsat_core_size();
-            for (unsigned i = 0; i < sz; i++)
-                r.push_back(ctx().get_unsat_core_expr(i));            
-        }
-        virtual void get_model(model_ref & m) { ctx().get_model(m); }
-        virtual proof * get_proof() { return ctx().get_proof(); }
-        virtual std::string reason_unknown() const { return ctx().last_failure_as_string(); }
-        virtual void get_labels(svector<symbol> & r) {
-            buffer<symbol> tmp;
-            ctx().get_relevant_labels(0, tmp);
-            r.append(tmp.size(), tmp.c_ptr());            
-        }
-        
-        // These are controlled by the main API
-        virtual void set_cancel(bool f) { }
-        void cancel() { set_cancel(true); }
-        void reset_cancel() { set_cancel(false); }        
-        virtual void set_progress_callback(progress_callback * callback) {}        
-    };
-
     Z3_ast parse_smtlib2_stream(bool exec, Z3_context c, std::istream& is,
                                 unsigned num_sorts,
                                 Z3_symbol const sort_names[],
@@ -298,9 +262,6 @@ extern "C" {
         Z3_TRY;
         cmd_context ctx(false, &(mk_c(c)->m()));
         ctx.set_ignore_check(true);
-        if (exec) {
-            ctx.set_solver(alloc(z3_context_solver, *mk_c(c)));
-        }
         for (unsigned i = 0; i < num_decls; ++i) {
            ctx.insert(to_symbol(decl_names[i]), to_func_decl(decls[i]));
         }
@@ -353,39 +314,4 @@ extern "C" {
         RETURN_Z3(r);
         Z3_CATCH_RETURN(0);
     }
-
-    Z3_ast Z3_API Z3_exec_smtlib2_string(Z3_context c, Z3_string str,
-                                         unsigned num_sorts,
-                                         Z3_symbol sort_names[],
-                                         Z3_sort sorts[],
-                                         unsigned num_decls,
-                                         Z3_symbol decl_names[],
-                                         Z3_func_decl decls[]) { 
-        Z3_TRY;
-        cmd_context ctx(false, &(mk_c(c)->m()));
-        std::string s(str);
-        std::istringstream is(s);
-        // No logging for this one, since it private.
-        return parse_smtlib2_stream(true, c, is, num_sorts, sort_names, sorts, num_decls, decl_names, decls);
-        Z3_CATCH_RETURN(0);
-    }
-
-    Z3_ast Z3_API Z3_exec_smtlib2_file(Z3_context c, Z3_string file_name,
-                                       unsigned num_sorts,
-                                       Z3_symbol sort_names[],
-                                       Z3_sort sorts[],
-                                       unsigned num_decls,
-                                       Z3_symbol decl_names[],
-                                       Z3_func_decl decls[]) { 
-        Z3_TRY;
-        std::ifstream is(file_name);
-        if (!is) {
-            SET_ERROR_CODE(Z3_PARSER_ERROR);
-            return 0;
-        }
-        // No logging for this one, since it private.
-        return parse_smtlib2_stream(true, c, is, num_sorts, sort_names, sorts, num_decls, decl_names, decls);
-        Z3_CATCH_RETURN(0);
-    }
-
 };
diff --git a/src/api/api_solver.cpp b/src/api/api_solver.cpp
index 89bfd9519..9ace149af 100644
--- a/src/api/api_solver.cpp
+++ b/src/api/api_solver.cpp
@@ -30,19 +30,20 @@ Revision History:
 #include"scoped_timer.h"
 #include"smt_strategic_solver.h"
 #include"smt_solver.h"
+#include"smt_implied_equalities.h"
 
 extern "C" {
 
     static void init_solver_core(Z3_context c, Z3_solver _s) {
-        ast_manager & m = mk_c(c)->m();
         Z3_solver_ref * s = to_solver(_s);
-        mk_c(c)->params().init_solver_params(mk_c(c)->m(), *(s->m_solver), s->m_params);
-        s->m_solver->init(m, s->m_logic);
-        s->m_initialized = true;
+        bool proofs_enabled, models_enabled, unsat_core_enabled;
+        params_ref p = s->m_params;
+        mk_c(c)->params().get_solver_params(mk_c(c)->m(), p, proofs_enabled, models_enabled, unsat_core_enabled);
+        s->m_solver = (*(s->m_solver_factory))(mk_c(c)->m(), p, proofs_enabled, models_enabled, unsat_core_enabled, s->m_logic);
     }
 
     static void init_solver(Z3_context c, Z3_solver s) {
-        if (!to_solver(s)->m_initialized)
+        if (to_solver(s)->m_solver.get() == 0)
             init_solver_core(c, s);
     }
 
@@ -50,8 +51,7 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_mk_simple_solver(c);
         RESET_ERROR_CODE();
-        Z3_solver_ref * s = alloc(Z3_solver_ref);
-        s->m_solver       = mk_smt_solver();
+        Z3_solver_ref * s = alloc(Z3_solver_ref, mk_smt_solver_factory());
         mk_c(c)->save_object(s);
         Z3_solver r = of_solver(s);
         RETURN_Z3(r);
@@ -62,8 +62,7 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_mk_solver(c);
         RESET_ERROR_CODE();
-        Z3_solver_ref * s = alloc(Z3_solver_ref);
-        s->m_solver       = mk_smt_strategic_solver();
+        Z3_solver_ref * s = alloc(Z3_solver_ref, mk_smt_strategic_solver_factory());
         mk_c(c)->save_object(s);
         Z3_solver r = of_solver(s);
         RETURN_Z3(r);
@@ -74,8 +73,7 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_mk_solver_for_logic(c, logic);
         RESET_ERROR_CODE();
-        Z3_solver_ref * s = alloc(Z3_solver_ref, to_symbol(logic));
-        s->m_solver       = mk_smt_strategic_solver(true /* force solver to use tactics even when auto_config is disabled */);
+        Z3_solver_ref * s = alloc(Z3_solver_ref, mk_smt_strategic_solver_factory(to_symbol(logic)));
         mk_c(c)->save_object(s);
         Z3_solver r = of_solver(s);
         RETURN_Z3(r);
@@ -86,8 +84,7 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_mk_solver_from_tactic(c, t);
         RESET_ERROR_CODE();
-        Z3_solver_ref * s = alloc(Z3_solver_ref);
-        s->m_solver       = alloc(tactic2solver, to_tactic_ref(t));
+        Z3_solver_ref * s = alloc(Z3_solver_ref, mk_tactic2solver_factory(to_tactic_ref(t)));
         mk_c(c)->save_object(s);
         Z3_solver r = of_solver(s);
         RETURN_Z3(r);
@@ -100,7 +97,12 @@ extern "C" {
         RESET_ERROR_CODE();
         std::ostringstream buffer;
         param_descrs descrs;
+        bool initialized = to_solver(s)->m_solver.get() != 0;
+        if (!initialized)
+            init_solver(c, s);
         to_solver_ref(s)->collect_param_descrs(descrs);
+        if (!initialized)
+            to_solver(s)->m_solver = 0;
         descrs.display(buffer);
         return mk_c(c)->mk_external_string(buffer.str());
         Z3_CATCH_RETURN("");
@@ -112,7 +114,12 @@ extern "C" {
         RESET_ERROR_CODE();
         Z3_param_descrs_ref * d = alloc(Z3_param_descrs_ref);
         mk_c(c)->save_object(d);
+        bool initialized = to_solver(s)->m_solver.get() != 0;
+        if (!initialized)
+            init_solver(c, s);
         to_solver_ref(s)->collect_param_descrs(d->m_descrs);
+        if (!initialized)
+            to_solver(s)->m_solver = 0;
         Z3_param_descrs r = of_param_descrs(d);
         RETURN_Z3(r);
         Z3_CATCH_RETURN(0);
@@ -122,7 +129,7 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_solver_set_params(c, s, p);
         RESET_ERROR_CODE();
-        if (to_solver(s)->m_initialized) {
+        if (to_solver(s)->m_solver) {
             bool old_model = to_solver(s)->m_params.get_bool("model", true);
             bool new_model = to_param_ref(p).get_bool("model", true);
             if (old_model != new_model)
@@ -176,8 +183,7 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_solver_reset(c, s);
         RESET_ERROR_CODE();
-        to_solver_ref(s)->reset();
-        to_solver(s)->m_initialized = false;
+        to_solver(s)->m_solver = 0;
         Z3_CATCH;
     }
     
@@ -352,4 +358,22 @@ extern "C" {
         return mk_c(c)->mk_external_string(buffer.str());
         Z3_CATCH_RETURN("");
     }
+
+
+    Z3_lbool Z3_API Z3_get_implied_equalities(Z3_context c, 
+                                              Z3_solver s,
+                                              unsigned num_terms,
+                                              Z3_ast const terms[],
+                                              unsigned class_ids[]) {
+        Z3_TRY;
+        LOG_Z3_get_implied_equalities(c, s, num_terms, terms, class_ids);
+        ast_manager& m = mk_c(c)->m();
+        RESET_ERROR_CODE();
+        CHECK_SEARCHING(c);
+        init_solver(c, s);
+        lbool result = smt::implied_equalities(m, *to_solver_ref(s), num_terms, to_exprs(terms), class_ids);
+        return static_cast<Z3_lbool>(result); 
+        Z3_CATCH_RETURN(Z3_L_UNDEF);
+    }
+
 };
diff --git a/src/api/api_solver.h b/src/api/api_solver.h
index 1569ef0da..f11c9bfd8 100644
--- a/src/api/api_solver.h
+++ b/src/api/api_solver.h
@@ -22,17 +22,16 @@ Revision History:
 #include"solver.h"
 
 struct Z3_solver_ref : public api::object {
-    solver *   m_solver;
-    params_ref m_params;
-    bool       m_initialized;
-    symbol     m_logic;
-    Z3_solver_ref():m_solver(0), m_initialized(false), m_logic(symbol::null) {}
-    Z3_solver_ref(symbol const & logic):m_solver(0), m_initialized(false), m_logic(logic) {}
-    virtual ~Z3_solver_ref() { dealloc(m_solver); }
+    scoped_ptr<solver_factory> m_solver_factory;
+    ref<solver>                m_solver;
+    params_ref                 m_params;
+    symbol                     m_logic;
+    Z3_solver_ref(solver_factory * f):m_solver_factory(f), m_solver(0), m_logic(symbol::null) {}
+    virtual ~Z3_solver_ref() {}
 };
 
 inline Z3_solver_ref * to_solver(Z3_solver s) { return reinterpret_cast<Z3_solver_ref *>(s); }
 inline Z3_solver of_solver(Z3_solver_ref * s) { return reinterpret_cast<Z3_solver>(s); }
-inline solver * to_solver_ref(Z3_solver s) { return to_solver(s)->m_solver; }
+inline solver * to_solver_ref(Z3_solver s) { return to_solver(s)->m_solver.get(); }
 
 #endif
diff --git a/src/api/api_solver_old.cpp b/src/api/api_solver_old.cpp
index cd4b797e3..c89f89873 100644
--- a/src/api/api_solver_old.cpp
+++ b/src/api/api_solver_old.cpp
@@ -22,7 +22,6 @@ Revision History:
 #include"api_log_macros.h"
 #include"api_context.h"
 #include"api_model.h"
-#include"smt_implied_equalities.h"
 #include"cancel_eh.h"
 
 extern "C" {
@@ -112,19 +111,6 @@ extern "C" {
         Z3_CATCH_RETURN(Z3_L_UNDEF);
     }
 
-    Z3_lbool Z3_API Z3_get_implied_equalities(Z3_context c, 
-                                              unsigned num_terms,
-                                              Z3_ast const terms[],
-                                              unsigned class_ids[]) {
-        Z3_TRY;
-        LOG_Z3_get_implied_equalities(c, num_terms, terms, class_ids);
-        RESET_ERROR_CODE();
-        CHECK_SEARCHING(c);
-        lbool result = smt::implied_equalities(mk_c(c)->get_smt_kernel(), num_terms, to_exprs(terms), class_ids);
-        return static_cast<Z3_lbool>(result); 
-        Z3_CATCH_RETURN(Z3_L_UNDEF);
-    }
-
     
     Z3_lbool Z3_API Z3_check_assumptions(Z3_context c, 
                                          unsigned num_assumptions, Z3_ast const assumptions[], 
diff --git a/src/api/ml/Makefile.build b/src/api/ml/Makefile.build
index 27c798bbf..0a737e356 100644
--- a/src/api/ml/Makefile.build
+++ b/src/api/ml/Makefile.build
@@ -13,7 +13,7 @@ XCDBG=-g $(CFLAGS)
 XCOPT=-ccopt -Ox -ccopt -Oy- $(CFLAGS)
 # ole32 is needed by camlidl (COM support)
 XLIB=-cclib ole32.lib
-AR=lib /nologo /LIBPATH:../../build ../../z3.lib /out:
+AR=lib /nologo /LIBPATH:../../build ../../libz3.lib /out:
 O=obj
 A=lib
 else
diff --git a/src/api/ml/README-linux b/src/api/ml/README-linux
index a726c0c94..5ee20bb27 100644
--- a/src/api/ml/README-linux
+++ b/src/api/ml/README-linux
@@ -1,22 +1,22 @@
-The OCaml API for Z3 was tested using OCaml 3.12.1.
-You also need CamlIDL to be able to generate the OCaml API.
-
-- To download OCaml:
-  http://caml.inria.fr/ocaml/      
-
-- To download CamlIDL:
-  http://forge.ocamlcore.org/projects/camlidl/
-
-- To build the OCaml API for Z3:
-  ./build-lib.sh
-
-Remark: The OCaml and C compiler tool chains must be configured in your environment.
-
-Remark: Building the OCaml API copies some pathnames into files,
-so the OCaml API must be recompiled if the Z3 library files are moved.
-
-See ../examples/ocaml/build-test.sh for an example of how to compile and link with Z3.
-
-Acknowledgements:
-The OCaml interface for Z3 was written by Josh Berdine and Jakob Lichtenberg. 
-Many thanks to them!
+The OCaml API for Z3 was tested using OCaml 3.12.1.
+You also need CamlIDL to be able to generate the OCaml API.
+
+- To download OCaml:
+  http://caml.inria.fr/ocaml/      
+
+- To download CamlIDL:
+  http://forge.ocamlcore.org/projects/camlidl/
+
+- To build the OCaml API for Z3:
+  ./build-lib.sh
+
+Remark: The OCaml and C compiler tool chains must be configured in your environment.
+
+Remark: Building the OCaml API copies some pathnames into files,
+so the OCaml API must be recompiled if the Z3 library files are moved.
+
+See ../examples/ocaml/build-test.sh for an example of how to compile and link with Z3.
+
+Acknowledgements:
+The OCaml interface for Z3 was written by Josh Berdine and Jakob Lichtenberg. 
+Many thanks to them!
diff --git a/src/api/ml/README-osx b/src/api/ml/README-osx
index a726c0c94..5ee20bb27 100644
--- a/src/api/ml/README-osx
+++ b/src/api/ml/README-osx
@@ -1,22 +1,22 @@
-The OCaml API for Z3 was tested using OCaml 3.12.1.
-You also need CamlIDL to be able to generate the OCaml API.
-
-- To download OCaml:
-  http://caml.inria.fr/ocaml/      
-
-- To download CamlIDL:
-  http://forge.ocamlcore.org/projects/camlidl/
-
-- To build the OCaml API for Z3:
-  ./build-lib.sh
-
-Remark: The OCaml and C compiler tool chains must be configured in your environment.
-
-Remark: Building the OCaml API copies some pathnames into files,
-so the OCaml API must be recompiled if the Z3 library files are moved.
-
-See ../examples/ocaml/build-test.sh for an example of how to compile and link with Z3.
-
-Acknowledgements:
-The OCaml interface for Z3 was written by Josh Berdine and Jakob Lichtenberg. 
-Many thanks to them!
+The OCaml API for Z3 was tested using OCaml 3.12.1.
+You also need CamlIDL to be able to generate the OCaml API.
+
+- To download OCaml:
+  http://caml.inria.fr/ocaml/      
+
+- To download CamlIDL:
+  http://forge.ocamlcore.org/projects/camlidl/
+
+- To build the OCaml API for Z3:
+  ./build-lib.sh
+
+Remark: The OCaml and C compiler tool chains must be configured in your environment.
+
+Remark: Building the OCaml API copies some pathnames into files,
+so the OCaml API must be recompiled if the Z3 library files are moved.
+
+See ../examples/ocaml/build-test.sh for an example of how to compile and link with Z3.
+
+Acknowledgements:
+The OCaml interface for Z3 was written by Josh Berdine and Jakob Lichtenberg. 
+Many thanks to them!
diff --git a/src/api/ml/README-test-linux b/src/api/ml/README-test-linux
index 34900883d..fc15fb2a2 100644
--- a/src/api/ml/README-test-linux
+++ b/src/api/ml/README-test-linux
@@ -1,17 +1,17 @@
-This directory contains scripts to build the test application using
-OCaml. You also need CamlIDL to be able to generate the OCaml API.
-
-- To download OCaml:
-  http://caml.inria.fr/ocaml/      
-
-- To download CamlIDL:
-  http://forge.ocamlcore.org/projects/camlidl/
-
-- One must build the OCaml library before compiling the example.
-  Go to directory ../ocaml
-
-- Use 'build-test.sh' to build the test application using the OCaml compiler.
-
-Remark: The OCaml and C compiler tool chains must be configured in your environment.
-  
-- Use 'exec.sh' to execute test_mlapi. The script sets LD_LIBRARY_PATH, and invokes test_mlapi.
+This directory contains scripts to build the test application using
+OCaml. You also need CamlIDL to be able to generate the OCaml API.
+
+- To download OCaml:
+  http://caml.inria.fr/ocaml/      
+
+- To download CamlIDL:
+  http://forge.ocamlcore.org/projects/camlidl/
+
+- One must build the OCaml library before compiling the example.
+  Go to directory ../ocaml
+
+- Use 'build-test.sh' to build the test application using the OCaml compiler.
+
+Remark: The OCaml and C compiler tool chains must be configured in your environment.
+  
+- Use 'exec.sh' to execute test_mlapi. The script sets LD_LIBRARY_PATH, and invokes test_mlapi.
diff --git a/src/api/ml/README-test-osx b/src/api/ml/README-test-osx
index bfc6b115e..3a20d1f1d 100644
--- a/src/api/ml/README-test-osx
+++ b/src/api/ml/README-test-osx
@@ -1,17 +1,17 @@
-This directory contains scripts to build the test application using
-OCaml. You also need CamlIDL to be able to generate the OCaml API.
-
-- To download OCaml:
-  http://caml.inria.fr/ocaml/      
-
-- To download CamlIDL:
-  http://forge.ocamlcore.org/projects/camlidl/
-
-- One must build the OCaml library before compiling the example.
-  Go to directory ../ocaml
-
-- Use 'build-test.sh' to build the test application using the OCaml compiler.
-
-Remark: The OCaml and C compiler tool chains must be configured in your environment.
-  
-- Use 'exec.sh' to execute test_mlapi. The script sets DYLD_LIBRARY_PATH, and invokes test_mlapi.
+This directory contains scripts to build the test application using
+OCaml. You also need CamlIDL to be able to generate the OCaml API.
+
+- To download OCaml:
+  http://caml.inria.fr/ocaml/      
+
+- To download CamlIDL:
+  http://forge.ocamlcore.org/projects/camlidl/
+
+- One must build the OCaml library before compiling the example.
+  Go to directory ../ocaml
+
+- Use 'build-test.sh' to build the test application using the OCaml compiler.
+
+Remark: The OCaml and C compiler tool chains must be configured in your environment.
+  
+- Use 'exec.sh' to execute test_mlapi. The script sets DYLD_LIBRARY_PATH, and invokes test_mlapi.
diff --git a/src/api/ml/exec.sh b/src/api/ml/exec.sh
index a1d3c8e49..573ec6ddf 100644
--- a/src/api/ml/exec.sh
+++ b/src/api/ml/exec.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
-export LD_LIBRARY_PATH=../../lib:$LD_LIBRARY_PATH	# for linux
-export DYLD_LIBRARY_PATH=../../lib:$DYLD_LIBRARY_PATH	# for osx
-./test_mlapi
+#!/bin/sh
+export LD_LIBRARY_PATH=../../lib:$LD_LIBRARY_PATH	# for linux
+export DYLD_LIBRARY_PATH=../../lib:$DYLD_LIBRARY_PATH	# for osx
+./test_mlapi
diff --git a/src/api/ml/z3.ml b/src/api/ml/z3.ml
index 7498a0d46..abedaeef8 100644
--- a/src/api/ml/z3.ml
+++ b/src/api/ml/z3.ml
@@ -229,16 +229,6 @@ and param_kind =
   | PK_OTHER
   | PK_INVALID
 
-and search_failure =
-  | NO_FAILURE
-  | UNKNOWN
-  | TIMEOUT
-  | MEMOUT_WATERMARK
-  | CANCELED
-  | NUM_CONFLICTS
-  | THEORY
-  | QUANTIFIERS
-
 and ast_print_mode =
   | PRINT_SMTLIB_FULL
   | PRINT_LOW_LEVEL
@@ -1596,6 +1586,9 @@ external stats_get_uint_value : context -> stats -> int -> int
 external stats_get_double_value : context -> stats -> int -> float
 	= "camlidl_z3_Z3_stats_get_double_value"
 
+external get_implied_equalities : context -> solver -> ast array -> lbool * int array
+	= "camlidl_z3_Z3_get_implied_equalities"
+
 
 
 (* Internal auxiliary functions: *)
@@ -3027,9 +3020,6 @@ external check : context -> lbool
 external check_assumptions : context -> ast array -> int -> ast array -> lbool * model * ast * int * ast array
 	= "camlidl_z3V3_Z3_check_assumptions"
 
-external get_implied_equalities : context -> ast array -> lbool * int array
-	= "camlidl_z3V3_Z3_get_implied_equalities"
-
 external del_model : context -> model -> unit
 	= "camlidl_z3V3_Z3_del_model"
 
diff --git a/src/api/ml/z3.mli b/src/api/ml/z3.mli
index 905716035..cf3c3d6c2 100644
--- a/src/api/ml/z3.mli
+++ b/src/api/ml/z3.mli
@@ -229,16 +229,6 @@ and param_kind =
   | PK_OTHER
   | PK_INVALID
 
-and search_failure =
-  | NO_FAILURE
-  | UNKNOWN
-  | TIMEOUT
-  | MEMOUT_WATERMARK
-  | CANCELED
-  | NUM_CONFLICTS
-  | THEORY
-  | QUANTIFIERS
-
 and ast_print_mode =
   | PRINT_SMTLIB_FULL
   | PRINT_LOW_LEVEL
@@ -1013,37 +1003,22 @@ and goal_prec =
     - PK_INVALID invalid parameter.
 *)
 (**
-    {!search_failure}  
-   The different kinds of search failure types.
-
-   - NO_FAILURE:         The last search was successful
-   - UNKNOWN:            Undocumented failure reason
-   - TIMEOUT:            Timeout
-   - MEMOUT_WATERMAK:    Search hit a memory high-watermak limit
-   - CANCELED:           External cancel flag was set
-   - NUM_CONFLICTS:      Maximum number of conflicts was reached
-   - THEORY:             Theory is incomplete
-   - QUANTIFIERS:        Logical context contains universal quantifiers
-*)
-(**
-    {!ast_print_mode}  
+    {!ast_print_mode}
    Z3 pretty printing modes (See {!set_ast_print_mode}).
-
-   - PRINT_SMTLIB_FULL:   Print AST nodes in SMTLIB verbose format.
-   - PRINT_LOW_LEVEL:     Print AST nodes using a low-level format.
+   - PRINT_SMTLIB_FULL: Print AST nodes in SMTLIB verbose format.
+   - PRINT_LOW_LEVEL: Print AST nodes using a low-level format.
    - PRINT_SMTLIB_COMPLIANT: Print AST nodes in SMTLIB 1.x compliant format.
    - PRINT_SMTLIB2_COMPLIANT: Print AST nodes in SMTLIB 2.x compliant format.
 *)
 (**
-    {!error_code}  
-   Z3 error codes 
-   
-   - OK:            No error.
-   - SORT_ERROR:    User tried to build an invalid (type incorrect) AST.
-   - IOB:           Index out of bounds.
-   - INVALID_ARG:   Invalid argument was provided.
-   - PARSER_ERROR:  An error occurred when parsing a string or file.
-   - NO_PARSER:     Parser output is not available, that is, user didn't invoke {!parse_smtlib_string} or {!parse_smtlib_file}.
+    {!error_code}
+   Z3 error codes
+   - OK: No error.
+   - SORT_ERROR: User tried to build an invalid (type incorrect) AST.
+   - IOB: Index out of bounds.
+   - INVALID_ARG: Invalid argument was provided.
+   - PARSER_ERROR: An error occurred when parsing a string or file.
+   - NO_PARSER: Parser output is not available, that is, user didn't invoke {!parse_smtlib_string} or {!parse_smtlib_file}.
    - INVALID_PATTERN: Invalid pattern was used to build a quantifier.
    - MEMOUT_FAIL:   A memory allocation failure was encountered.
    - FILE_ACCESS_ERRROR: A file could not be accessed.
@@ -1054,17 +1029,16 @@ and goal_prec =
 *)
 (**
   Definitions for update_api.py
-  
-  def_Type('CONFIG',           'config',           'Config')
-  def_Type('CONTEXT',          'context',          'ContextObj')
-  def_Type('AST',              'ast',              'Ast')
-  def_Type('APP',              'app',              'Ast')
-  def_Type('SORT',             'sort',             'Sort')
-  def_Type('FUNC_DECL',        'func_decl',        'FuncDecl')
-  def_Type('PATTERN',          'pattern',          'Pattern')
-  def_Type('MODEL',            'model',            'Model')
-  def_Type('LITERALS',         'literals',         'Literals')
-  def_Type('CONSTRUCTOR',      'constructor',      'Constructor')
+  def_Type('CONFIG', 'config', 'Config')
+  def_Type('CONTEXT', 'context', 'ContextObj')
+  def_Type('AST', 'ast', 'Ast')
+  def_Type('APP', 'app', 'Ast')
+  def_Type('SORT', 'sort', 'Sort')
+  def_Type('FUNC_DECL', 'func_decl', 'FuncDecl')
+  def_Type('PATTERN', 'pattern', 'Pattern')
+  def_Type('MODEL', 'model', 'Model')
+  def_Type('LITERALS', 'literals', 'Literals')
+  def_Type('CONSTRUCTOR', 'constructor', 'Constructor')
   def_Type('CONSTRUCTOR_LIST', 'constructor_list', 'ConstructorList')
   def_Type('THEORY',           'theory',           'ctypes.c_void_p')
   def_Type('THEORY_DATA',      'theory_data',      'ctypes.c_void_p')
@@ -6050,6 +6024,30 @@ external stats_get_uint_value : context -> stats -> int -> int
 external stats_get_double_value : context -> stats -> int -> float
 	= "camlidl_z3_Z3_stats_get_double_value"
 
+(**
+       {2 {L Deprecated Constraints API}}
+*)
+(**
+       Summary: Retrieve congruence class representatives for terms.
+       The function can be used for relying on Z3 to identify equal terms under the current
+       set of assumptions. The array of terms and array of class identifiers should have
+       the same length. The class identifiers are numerals that are assigned to the same
+       value for their corresponding terms if the current context forces the terms to be
+       equal. You cannot deduce that terms corresponding to different numerals must be all different,
+       (especially when using non-convex theories).
+       All implied equalities are returned by this call.
+       This means that two terms map to the same class identifier if and only if
+       the current context implies that they are equal.
+       A side-effect of the function is a satisfiability check on the assertions on the solver that is passed in.
+       The function return L_FALSE if the current assertions are not satisfiable.
+       - {b See also}: {!check_and_get_model}
+       - {b See also}: {!check}
+       @deprecated To be moved outside of API.
+       def_API('get_implied_equalities', UINT, (_in(CONTEXT), _in(SOLVER), _in(UINT), _in_array(2, AST), _out_array(2, UINT)))
+*)
+external get_implied_equalities : context -> solver -> ast array -> lbool * int array
+	= "camlidl_z3_Z3_get_implied_equalities"
+
 
 (** 
    {2 {L Legacy V3 API}} 
@@ -10595,32 +10593,6 @@ external check : context -> lbool
 external check_assumptions : context -> ast array -> int -> ast array -> lbool * model * ast * int * ast array
 	= "camlidl_z3V3_Z3_check_assumptions"
 
-(**
-       Summary: Retrieve congruence class representatives for terms.
-
-       The function can be used for relying on Z3 to identify equal terms under the current
-       set of assumptions. The array of terms and array of class identifiers should have
-       the same length. The class identifiers are numerals that are assigned to the same
-       value for their corresponding terms if the current context forces the terms to be
-       equal. You cannot deduce that terms corresponding to different numerals must be all different, 
-       (especially when using non-convex theories).
-       All implied equalities are returned by this call.
-       This means that two terms map to the same class identifier if and only if
-       the current context implies that they are equal.
-
-       A side-effect of the function is a satisfiability check.
-       The function return L_FALSE if the current assertions are not satisfiable.
-
-       - {b See also}: {!check_and_get_model}
-       - {b See also}: {!check}
-    
-       @deprecated Subsumed by solver API
-
-       def_API('get_implied_equalities', UINT, (_in(CONTEXT), _in(UINT), _in_array(1, AST), _out_array(1, UINT)))
-*)
-external get_implied_equalities : context -> ast array -> lbool * int array
-	= "camlidl_z3V3_Z3_get_implied_equalities"
-
 (**
        Summary: Delete a model object.
        
diff --git a/src/api/ml/z3_stubs.c b/src/api/ml/z3_stubs.c
index dcc434196..6286e94c7 100644
--- a/src/api/ml/z3_stubs.c
+++ b/src/api/ml/z3_stubs.c
@@ -605,30 +605,7 @@ value _v1;
   return _v1;
 }
 
-int camlidl_transl_table_z3_enum_8[8] = {
-  Z3_NO_FAILURE,
-  Z3_UNKNOWN,
-  Z3_TIMEOUT,
-  Z3_MEMOUT_WATERMARK,
-  Z3_CANCELED,
-  Z3_NUM_CONFLICTS,
-  Z3_THEORY,
-  Z3_QUANTIFIERS,
-};
-
-void camlidl_ml2c_z3_Z3_search_failure(value _v1, Z3_search_failure * _c2, camlidl_ctx _ctx)
-{
-  (*_c2) = camlidl_transl_table_z3_enum_8[Int_val(_v1)];
-}
-
-value camlidl_c2ml_z3_Z3_search_failure(Z3_search_failure * _c2, camlidl_ctx _ctx)
-{
-value _v1;
-  _v1 = camlidl_find_enum((*_c2), camlidl_transl_table_z3_enum_8, 8, "typedef Z3_search_failure: bad enum  value");
-  return _v1;
-}
-
-int camlidl_transl_table_z3_enum_9[4] = {
+int camlidl_transl_table_z3_enum_8[4] = {
   Z3_PRINT_SMTLIB_FULL,
   Z3_PRINT_LOW_LEVEL,
   Z3_PRINT_SMTLIB_COMPLIANT,
@@ -637,7 +614,7 @@ int camlidl_transl_table_z3_enum_9[4] = {
 
 void camlidl_ml2c_z3_Z3_ast_print_mode(value _v1, Z3_ast_print_mode * _c2, camlidl_ctx _ctx)
 {
-  (*_c2) = camlidl_transl_table_z3_enum_9[Int_val(_v1)];
+  (*_c2) = camlidl_transl_table_z3_enum_8[Int_val(_v1)];
 }
 
 value camlidl_c2ml_z3_Z3_ast_print_mode(Z3_ast_print_mode * _c2, camlidl_ctx _ctx)
@@ -653,7 +630,7 @@ value _v1;
   return _v1;
 }
 
-int camlidl_transl_table_z3_enum_10[13] = {
+int camlidl_transl_table_z3_enum_9[13] = {
   Z3_OK,
   Z3_SORT_ERROR,
   Z3_IOB,
@@ -671,13 +648,13 @@ int camlidl_transl_table_z3_enum_10[13] = {
 
 void camlidl_ml2c_z3_Z3_error_code(value _v1, Z3_error_code * _c2, camlidl_ctx _ctx)
 {
-  (*_c2) = camlidl_transl_table_z3_enum_10[Int_val(_v1)];
+  (*_c2) = camlidl_transl_table_z3_enum_9[Int_val(_v1)];
 }
 
 value camlidl_c2ml_z3_Z3_error_code(Z3_error_code * _c2, camlidl_ctx _ctx)
 {
 value _v1;
-  _v1 = camlidl_find_enum((*_c2), camlidl_transl_table_z3_enum_10, 13, "typedef Z3_error_code: bad enum  value");
+  _v1 = camlidl_find_enum((*_c2), camlidl_transl_table_z3_enum_9, 13, "typedef Z3_error_code: bad enum  value");
   return _v1;
 }
 
@@ -707,7 +684,7 @@ void check_error_code (Z3_context c)
 
 void* error_handler_static = NULL;
 
-int camlidl_transl_table_z3_enum_11[4] = {
+int camlidl_transl_table_z3_enum_10[4] = {
   Z3_GOAL_PRECISE,
   Z3_GOAL_UNDER,
   Z3_GOAL_OVER,
@@ -716,7 +693,7 @@ int camlidl_transl_table_z3_enum_11[4] = {
 
 void camlidl_ml2c_z3_Z3_goal_prec(value _v1, Z3_goal_prec * _c2, camlidl_ctx _ctx)
 {
-  (*_c2) = camlidl_transl_table_z3_enum_11[Int_val(_v1)];
+  (*_c2) = camlidl_transl_table_z3_enum_10[Int_val(_v1)];
 }
 
 value camlidl_c2ml_z3_Z3_goal_prec(Z3_goal_prec * _c2, camlidl_ctx _ctx)
@@ -11072,7 +11049,56 @@ check_error_code(c);
   return _vres;
 }
 
-void caml_z3_error_handler(Z3_context c, Z3_error_code e) { static char buffer[128]; char * msg = Z3_get_error_msg_ex(c, e); if (strlen(msg) > 100) { failwith("Z3: error message is too big to fit in buffer"); } else { sprintf(buffer, "Z3: %s", msg); failwith(buffer); } }
+value camlidl_z3_Z3_get_implied_equalities(
+	value _v_c,
+	value _v_s,
+	value _v_terms)
+{
+  Z3_context c; /*in*/
+  Z3_solver s; /*in*/
+  unsigned int num_terms; /*in*/
+  Z3_ast const *terms; /*in*/
+  unsigned int *class_ids; /*out*/
+  Z3_lbool _res;
+  struct camlidl_ctx_struct _ctxs = { CAMLIDL_TRANSIENT, NULL };
+  camlidl_ctx _ctx = &_ctxs;
+  mlsize_t _c1;
+  mlsize_t _c2;
+  value _v3;
+  mlsize_t _c4;
+  value _v5;
+  value _vresult;
+  value _vres[2] = { 0, 0, };
+
+  camlidl_ml2c_z3_Z3_context(_v_c, &c, _ctx);
+  camlidl_ml2c_z3_Z3_solver(_v_s, &s, _ctx);
+  _c1 = Wosize_val(_v_terms);
+  terms = camlidl_malloc(_c1 * sizeof(Z3_ast const ), _ctx);
+  for (_c2 = 0; _c2 < _c1; _c2++) {
+    _v3 = Field(_v_terms, _c2);
+    camlidl_ml2c_z3_Z3_ast(_v3, &terms[_c2], _ctx);
+  }
+  num_terms = _c1;
+  class_ids = camlidl_malloc(num_terms * sizeof(unsigned int ), _ctx);
+  _res = Z3_get_implied_equalities(c, s, num_terms, terms, class_ids);
+  Begin_roots_block(_vres, 2)
+    _vres[0] = camlidl_c2ml_z3_Z3_lbool(&_res, _ctx);
+    _vres[1] = camlidl_alloc(num_terms, 0);
+    for (_c4 = 0; _c4 < num_terms; _c4++) {
+      _v5 = Val_int(class_ids[_c4]);
+      modify(&Field(_vres[1], _c4), _v5);
+    }
+    _vresult = camlidl_alloc_small(2, 0);
+    Field(_vresult, 0) = _vres[0];
+    Field(_vresult, 1) = _vres[1];
+  End_roots()
+  camlidl_free(_ctx);
+  /* begin user-supplied deallocation sequence */
+check_error_code(c);
+  /* end user-supplied deallocation sequence */
+  return _vresult;
+}
+
 void camlidl_ml2c_z3V3_Z3_symbol(value _v1, Z3_symbol * _c2, camlidl_ctx _ctx)
 {
   *_c2 = *((Z3_symbol *) Bp_val(_v1));
@@ -18250,50 +18276,6 @@ value camlidl_z3V3_Z3_check_assumptions(
   return _vresult;
 }
 
-value camlidl_z3V3_Z3_get_implied_equalities(
-	value _v_c,
-	value _v_terms)
-{
-  Z3_context c; /*in*/
-  unsigned int num_terms; /*in*/
-  Z3_ast const *terms; /*in*/
-  unsigned int *class_ids; /*out*/
-  Z3_lbool _res;
-  struct camlidl_ctx_struct _ctxs = { CAMLIDL_TRANSIENT, NULL };
-  camlidl_ctx _ctx = &_ctxs;
-  mlsize_t _c1;
-  mlsize_t _c2;
-  value _v3;
-  mlsize_t _c4;
-  value _v5;
-  value _vresult;
-  value _vres[2] = { 0, 0, };
-
-  camlidl_ml2c_z3V3_Z3_context(_v_c, &c, _ctx);
-  _c1 = Wosize_val(_v_terms);
-  terms = camlidl_malloc(_c1 * sizeof(Z3_ast const ), _ctx);
-  for (_c2 = 0; _c2 < _c1; _c2++) {
-    _v3 = Field(_v_terms, _c2);
-    camlidl_ml2c_z3V3_Z3_ast(_v3, &terms[_c2], _ctx);
-  }
-  num_terms = _c1;
-  class_ids = camlidl_malloc(num_terms * sizeof(unsigned int ), _ctx);
-  _res = Z3_get_implied_equalities(c, num_terms, terms, class_ids);
-  Begin_roots_block(_vres, 2)
-    _vres[0] = camlidl_c2ml_z3V3_Z3_lbool(&_res, _ctx);
-    _vres[1] = camlidl_alloc(num_terms, 0);
-    for (_c4 = 0; _c4 < num_terms; _c4++) {
-      _v5 = Val_int(class_ids[_c4]);
-      modify(&Field(_vres[1], _c4), _v5);
-    }
-    _vresult = camlidl_alloc_small(2, 0);
-    Field(_vresult, 0) = _vres[0];
-    Field(_vresult, 1) = _vres[1];
-  End_roots()
-  camlidl_free(_ctx);
-  return _vresult;
-}
-
 value camlidl_z3V3_Z3_del_model(
 	value _v_c,
 	value _v_m)
diff --git a/src/api/python/z3.py b/src/api/python/z3.py
index 924ac0ea5..9b1d5f1f0 100644
--- a/src/api/python/z3.py
+++ b/src/api/python/z3.py
@@ -37,15 +37,23 @@ Z3 exceptions:
 ...   # the expression x + y is type incorrect
 ...   n = x + y
 ... except Z3Exception as ex:
-...   print "failed:", ex
+...   print("failed: %s" % ex)
 failed: 'sort mismatch'
 """
 from z3core import *
 from z3types import *
 from z3consts import *
 from z3printer import *
+import sys
 import io
 
+if sys.version < '3':
+    def _is_int(v):
+        return isinstance(v, int) or isinstance(v, long)
+else:
+    def _is_int(v):
+        return isinstance(v, int)
+
 def enable_trace(msg):
     Z3_enable_trace(msg)
 
@@ -102,12 +110,12 @@ _error_handler_fptr = ctypes.CFUNCTYPE(None, ctypes.c_void_p, ctypes.c_uint)
 # list of arguments.
 def _get_args(args):
     try:
-	if len(args) == 1 and (isinstance(args[0], tuple) or isinstance(args[0], list)):
-	    return args[0]
-	else:
-	    return args
+        if len(args) == 1 and (isinstance(args[0], tuple) or isinstance(args[0], list)):
+            return args[0]
+        else:
+            return args
     except:  # len is not necessarily defined when args is not a sequence (use reflection?)
-	return args
+        return args
 
 def _Z3python_error_handler_core(c, e):
     # Do nothing error handler, just avoid exit(0)
@@ -140,7 +148,8 @@ class Context:
         if __debug__:
             _z3_assert(len(args) % 2 == 0, "Argument list must have an even number of elements.")
         conf = Z3_mk_config()
-        for key, value in kws.iteritems():
+        for key in kws:
+            value = kws[key]
             Z3_set_param_value(conf, str(key).upper(), _to_param_value(value))
         prev = None
         for a in args:
@@ -209,10 +218,12 @@ def set_param(*args, **kws):
     if __debug__:
         _z3_assert(len(args) % 2 == 0, "Argument list must have an even number of elements.")
     new_kws = {}
-    for k, v in kws.iteritems():
+    for k in kws:
+        v = kws[k]
         if not set_pp_option(k, v):
             new_kws[k] = v
-    for key, value in new_kws.iteritems():
+    for key in new_kws:
+        value = new_kws[key]
         Z3_global_param_set(str(key).upper(), _to_param_value(value))
     prev = None
     for a in args:
@@ -240,7 +251,7 @@ def get_param(name):
     """
     ptr = (ctypes.c_char_p * 1)()
     if Z3_global_param_get(str(name), ptr):
-        r = str(ptr[0])
+        r = z3core._to_pystr(ptr[0])
         return r
     raise Z3Exception("failed to retrieve value for '%s'" % name)
 
@@ -899,11 +910,22 @@ def _coerce_exprs(a, b, ctx=None):
     b = s.cast(b)
     return (a, b)
     
+def _reduce(f, l, a):
+    r = a
+    for e in l:
+        r = f(r, e)
+    return r
+
 def _coerce_expr_list(alist, ctx=None):
-    if filter(is_expr, alist) == []:
-        alist = map(lambda a: _py2expr(a, ctx), alist)
-    s = reduce(_coerce_expr_merge, alist, None)
-    return map(lambda a: s.cast(a), alist)
+    has_expr = False
+    for a in alist:
+        if is_expr(a):
+            has_expr = True
+            break
+    if not has_expr:
+        alist = [ _py2expr(a, ctx) for a in alist ]
+    s = _reduce(_coerce_expr_merge, alist, None)
+    return [ s.cast(a) for a in alist ]
 
 def is_expr(a):
     """Return `True` if `a` is a Z3 expression.
@@ -1518,7 +1540,7 @@ def MultiPattern(*args):
     """
     if __debug__:
         _z3_assert(len(args) > 0, "At least one argument expected")
-        _z3_assert(all(map(is_expr, args)), "Z3 expressions expected")
+        _z3_assert(all([ is_expr(a) for a in args ]), "Z3 expressions expected")
     ctx = args[0].ctx
     args, sz = _to_ast_array(args)
     return PatternRef(Z3_mk_pattern(ctx.ref(), sz, args), ctx)
@@ -1695,9 +1717,9 @@ def is_quantifier(a):
 def _mk_quantifier(is_forall, vs, body, weight=1, qid="", skid="", patterns=[], no_patterns=[]):
     if __debug__:
         _z3_assert(is_bool(body), "Z3 expression expected")
-        _z3_assert(is_const(vs) or (len(vs) > 0 and all(map(is_const, vs))), "Invalid bounded variable(s)")
-        _z3_assert(all(map(lambda a: is_pattern(a) or is_expr(a), patterns)), "Z3 patterns expected")
-        _z3_assert(all(map(is_expr, no_patterns)), "no patterns are Z3 expressions")
+        _z3_assert(is_const(vs) or (len(vs) > 0 and all([ is_const(v) for v in vs])), "Invalid bounded variable(s)")
+        _z3_assert(all([is_pattern(a) or is_expr(a) for a in patterns]), "Z3 patterns expected")
+        _z3_assert(all([is_expr(p) for p in no_patterns]), "no patterns are Z3 expressions")
     ctx = body.ctx
     if is_app(vs):
         vs = [vs]
@@ -1706,7 +1728,7 @@ def _mk_quantifier(is_forall, vs, body, weight=1, qid="", skid="", patterns=[],
     for i in range(num_vars):
         ## TODO: Check if is constant
         _vs[i] = vs[i].as_ast()
-    patterns = map(_to_pattern, patterns)
+    patterns = [ _to_pattern(p) for p in patterns ]
     num_pats = len(patterns)
     _pats = (Pattern * num_pats)()
     for i in range(num_pats):
@@ -2008,7 +2030,7 @@ class ArithRef(ExprRef):
 
     def __truediv__(self, other):
         """Create the Z3 expression `other/self`."""
-        self.__div__(other)
+        return self.__div__(other)
 
     def __rdiv__(self, other):
         """Create the Z3 expression `other/self`.
@@ -2029,7 +2051,7 @@ class ArithRef(ExprRef):
 
     def __rtruediv__(self, other):
         """Create the Z3 expression `other/self`."""
-        self.__rdiv__(other)
+        return self.__rdiv__(other)
 
     def __mod__(self, other):
         """Create the Z3 expression `other%self`.
@@ -2413,11 +2435,11 @@ class IntNumRef(ArithRef):
         >>> v + 1
         1 + 1
         >>> v.as_long() + 1
-        2L
+        2
         """
         if __debug__:
             _z3_assert(self.is_int(), "Integer value expected")
-        return long(self.as_string())
+        return int(self.as_string())
 
     def as_string(self):
         """Return a Z3 integer numeral as a Python string.
@@ -2464,8 +2486,8 @@ class RatNumRef(ArithRef):
         10000000000
         >>> v + 1
         10000000000 + 1
-        >>> v.numerator_as_long() + 1
-        10000000001L
+        >>> v.numerator_as_long() + 1 == 10000000001
+        True
         """
         return self.numerator().as_long()
         
@@ -2476,7 +2498,7 @@ class RatNumRef(ArithRef):
         >>> v
         1/3
         >>> v.denominator_as_long()
-        3L
+        3
         """
         return self.denominator().as_long()
 
@@ -2529,7 +2551,7 @@ class AlgebraicNumRef(ArithRef):
 def _py2expr(a, ctx=None):
     if isinstance(a, bool):
         return BoolVal(a, ctx)
-    if isinstance(a, int) or isinstance(a, long):
+    if _is_int(a):
         return IntVal(a, ctx)
     if isinstance(a, float):
         return RealVal(a, ctx)
@@ -2576,9 +2598,7 @@ def _to_int_str(val):
             return "1"
         else:
             return "0"
-    elif isinstance(val, int):
-        return str(val)
-    elif isinstance(val, long):
+    elif _is_int(val):
         return str(val)
     elif isinstance(val, str):
         return val
@@ -2625,8 +2645,8 @@ def RatVal(a, b, ctx=None):
     Real
     """
     if __debug__:
-        _z3_assert(isinstance(a, int) or isinstance(a, str) or isinstance(a, long), "First argument cannot be converted into an integer")
-        _z3_assert(isinstance(b, int) or isinstance(b, str) or isinstance(a, long), "Second argument cannot be converted into an integer")
+        _z3_assert(_is_int(a) or isinstance(a, str), "First argument cannot be converted into an integer")
+        _z3_assert(_is_int(b) or isinstance(b, str), "Second argument cannot be converted into an integer")
     return simplify(RealVal(a, ctx)/RealVal(b, ctx))
 
 def Q(a, b, ctx=None):
@@ -3078,7 +3098,7 @@ class BitVecRef(ExprRef):
 
     def __truediv__(self, other):
         """Create the Z3 expression (signed) division `self / other`."""
-        self.__div__(other)
+        return self.__div__(other)
 
     def __rdiv__(self, other):
         """Create the Z3 expression (signed) division `other / self`.
@@ -3098,7 +3118,7 @@ class BitVecRef(ExprRef):
 
     def __rtruediv__(self, other):
         """Create the Z3 expression (signed) division `other / self`."""
-        self.__rdiv__(other)
+        return self.__rdiv__(other)
 
     def __mod__(self, other):
         """Create the Z3 expression (signed) mod `self % other`.
@@ -3218,9 +3238,9 @@ class BitVecRef(ExprRef):
         >>> BitVecVal(4, 3)
         4
         >>> BitVecVal(4, 3).as_signed_long()
-        -4L
+        -4
         >>> simplify(BitVecVal(4, 3) >> 1).as_signed_long()
-        -2L
+        -2
         >>> simplify(BitVecVal(4, 3) >> 1)
         6
         >>> simplify(LShR(BitVecVal(4, 3), 1))
@@ -3284,32 +3304,32 @@ class BitVecNumRef(BitVecRef):
         >>> v = BitVecVal(0xbadc0de, 32)
         >>> v
         195936478
-        >>> print "0x%.8x" % v.as_long()
+        >>> print("0x%.8x" % v.as_long())
         0x0badc0de
         """
-        return long(self.as_string())
+        return int(self.as_string())
 
     def as_signed_long(self):
         """Return a Z3 bit-vector numeral as a Python long (bignum) numeral. The most significant bit is assumed to be the sign.
         
         >>> BitVecVal(4, 3).as_signed_long()
-        -4L
+        -4
         >>> BitVecVal(7, 3).as_signed_long()
-        -1L
+        -1
         >>> BitVecVal(3, 3).as_signed_long()
-        3L
-        >>> BitVecVal(2L**32 - 1, 32).as_signed_long()
-        -1L
-        >>> BitVecVal(2L**64 - 1, 64).as_signed_long()
-        -1L
+        3
+        >>> BitVecVal(2**32 - 1, 32).as_signed_long()
+        -1
+        >>> BitVecVal(2**64 - 1, 64).as_signed_long()
+        -1
         """
-        sz = long(self.size())
+        sz = self.size()
         val = self.as_long()
-        if val >= 2L**(sz - 1):
-            val = val - 2L**sz
-        if val < -2L**(sz - 1):
-            val = val + 2L**sz
-        return val
+        if val >= 2**(sz - 1):
+            val = val - 2**sz
+        if val < -2**(sz - 1):
+            val = val + 2**sz
+        return int(val)
 
     def as_string(self):
         return Z3_get_numeral_string(self.ctx_ref(), self.as_ast())
@@ -3379,7 +3399,7 @@ def BitVecVal(val, bv, ctx=None):
     >>> v = BitVecVal(10, 32)
     >>> v
     10
-    >>> print "0x%.8x" % v.as_long()
+    >>> print("0x%.8x" % v.as_long())
     0x0000000a
     """
     if is_bv_sort(bv):
@@ -3440,12 +3460,12 @@ def Concat(*args):
     Concat(Concat(1, 1 + 1), 1)
     >>> simplify(Concat(v, v+1, v))
     289
-    >>> print "%.3x" % simplify(Concat(v, v+1, v)).as_long()
+    >>> print("%.3x" % simplify(Concat(v, v+1, v)).as_long())
     121
     """
     args = _get_args(args)
     if __debug__:
-        _z3_assert(all(map(is_bv, args)), "All arguments must be Z3 bit-vector expressions.")
+        _z3_assert(all([is_bv(a) for a in args]), "All arguments must be Z3 bit-vector expressions.")
         _z3_assert(len(args) >= 2, "At least two arguments expected.")
     ctx = args[0].ctx
     r   = args[0]
@@ -3615,9 +3635,9 @@ def LShR(a, b):
     >>> BitVecVal(4, 3)
     4
     >>> BitVecVal(4, 3).as_signed_long()
-    -4L
+    -4
     >>> simplify(BitVecVal(4, 3) >> 1).as_signed_long()
-    -2L
+    -2
     >>> simplify(BitVecVal(4, 3) >> 1)
     6
     >>> simplify(LShR(BitVecVal(4, 3), 1))
@@ -3682,7 +3702,7 @@ def SignExt(n, a):
     254
     >>> v.size()
     8
-    >>> print "%.x" % v.as_long()
+    >>> print("%.x" % v.as_long())
     fe
     """
     if __debug__:
@@ -3727,12 +3747,12 @@ def RepeatBitVec(n, a):
     >>> n.size()
     32
     >>> v0 = BitVecVal(10, 4)
-    >>> print "%.x" % v0.as_long()
+    >>> print("%.x" % v0.as_long())
     a
     >>> v = simplify(RepeatBitVec(4, v0))
     >>> v.size()
     16
-    >>> print "%.x" % v.as_long()
+    >>> print("%.x" % v.as_long())
     aaaa
     """
     if __debug__:
@@ -4006,7 +4026,7 @@ def Map(f, *args):
     if __debug__:
         _z3_assert(len(args) > 0, "At least one Z3 array expression expected")
         _z3_assert(is_func_decl(f), "First argument must be a Z3 function declaration")
-        _z3_assert(all(map(is_array, args)), "Z3 array expected expected")
+        _z3_assert(all([is_array(a) for a in args]), "Z3 array expected expected")
         _z3_assert(len(args) == f.arity(), "Number of arguments mismatch")
     _args, sz = _to_ast_array(args)
     ctx = f.ctx
@@ -4100,7 +4120,7 @@ class Datatype:
         if __debug__:
             _z3_assert(isinstance(name, str), "String expected")
             _z3_assert(isinstance(rec_name, str), "String expected")
-            _z3_assert(all(map(_valid_accessor, args)), "Valid list of accessors expected. An accessor is a pair of the form (String, Datatype|Sort)")
+            _z3_assert(all([_valid_accessor(a) for a in args]), "Valid list of accessors expected. An accessor is a pair of the form (String, Datatype|Sort)")
         self.constructors.append((name, rec_name, args))
 
     def declare(self, name, *args):
@@ -4187,9 +4207,9 @@ def CreateDatatypes(*ds):
     ds = _get_args(ds)
     if __debug__:
         _z3_assert(len(ds) > 0, "At least one Datatype must be specified")
-        _z3_assert(all(map(lambda d: isinstance(d, Datatype), ds)), "Arguments must be Datatypes")
-        _z3_assert(all(map(lambda d: d.ctx == ds[0].ctx, ds)), "Context mismatch")
-        _z3_assert(all(map(lambda d: d.constructors != [], ds)), "Non-empty Datatypes expected")
+        _z3_assert(all([isinstance(d, Datatype) for d in ds]), "Arguments must be Datatypes")
+        _z3_assert(all([d.ctx == ds[0].ctx for d in  ds]), "Context mismatch")
+        _z3_assert(all([d.constructors != [] for d in ds]), "Non-empty Datatypes expected")
     ctx = ds[0].ctx
     num    = len(ds)
     names  = (Symbol * num)()
@@ -4355,7 +4375,7 @@ def EnumSort(name, values, ctx=None):
     """
     if __debug__:
         _z3_assert(isinstance(name, str), "Name must be a string")
-        _z3_assert(all(map(lambda v: isinstance(v, str), values)), "Eumeration sort values must be strings")
+        _z3_assert(all([isinstance(v, str) for v in values]), "Eumeration sort values must be strings")
         _z3_assert(len(values) > 0, "At least one value expected")
     ctx = _get_ctx(ctx)
     num = len(values)
@@ -4369,7 +4389,7 @@ def EnumSort(name, values, ctx=None):
     V = []
     for i in range(num):
         V.append(FuncDeclRef(_values[i], ctx))
-    V = map(lambda a: a(), V)
+    V = [a() for a in V]
     return S, V
 
 #########################################
@@ -4432,7 +4452,8 @@ def args2params(arguments, keywords, ctx=None):
         else:
             r.set(prev, a)
             prev = None
-    for k, v in keywords.iteritems():
+    for k in keywords:
+        v = keywords[k]
         r.set(k, v)
     return r
 
@@ -4469,7 +4490,7 @@ class ParamDescrsRef:
         return Z3_param_descrs_get_kind(self.ctx.ref(), self.descr, to_symbol(n, self.ctx))
     
     def __getitem__(self, arg):
-        if isinstance(arg, int) or isinstance(arg, long):
+        if _is_int(arg):
             return self.get_name(arg)
         else:
             return self.get_kind(arg)
@@ -5057,7 +5078,7 @@ class FuncEntry:
         >>> try:
         ...   e.arg_value(2)
         ... except IndexError:
-        ...   print "index error"
+        ...   print("index error")
         index error
         """
         if idx >= self.num_args():
@@ -5122,7 +5143,10 @@ class FuncInterp(Z3PPObject):
             Z3_func_interp_dec_ref(self.ctx.ref(), self.f)
 
     def else_value(self):
-        """Return the `else` value for a function interpretation.
+        """
+        Return the `else` value for a function interpretation.
+        Return None if Z3 did not specify the `else` value for
+        this object.
 
         >>> f = Function('f', IntSort(), IntSort())
         >>> s = Solver()
@@ -5135,7 +5159,11 @@ class FuncInterp(Z3PPObject):
         >>> m[f].else_value()
         1
         """
-        return _to_expr_ref(Z3_func_interp_get_else(self.ctx.ref(), self.f), self.ctx)
+        r = Z3_func_interp_get_else(self.ctx.ref(), self.f)
+        if r:
+            return _to_expr_ref(r, self.ctx)
+        else:
+            return None
 
     def num_entries(self):
         """Return the number of entries/points in the function interpretation `self`.
@@ -5428,7 +5456,7 @@ class ModelRef(Z3PPObject):
         1
         >>> m[f]
         [1 -> 0, else -> 0]
-        >>> for d in m: print "%s -> %s" % (d, m[d])
+        >>> for d in m: print("%s -> %s" % (d, m[d]))
         x -> 1
         f -> [1 -> 0, else -> 0]
         """
@@ -5499,16 +5527,16 @@ class Statistics:
         if in_html_mode():
             out = io.StringIO()
             even = True
-            out.write(u'<table border="1" cellpadding="2" cellspacing="0">')
+            out.write(u('<table border="1" cellpadding="2" cellspacing="0">'))
             for k, v in self:
                 if even:
-                    out.write(u'<tr style="background-color:#CFCFCF">')
+                    out.write(u('<tr style="background-color:#CFCFCF">'))
                     even = False
                 else:
-                    out.write(u'<tr>')
+                    out.write(u('<tr>'))
                     even = True
-                out.write(u'<td>%s</td><td>%s</td></tr>' % (k, v))
-            out.write(u'</table>')
+                out.write(u('<td>%s</td><td>%s</td></tr>' % (k, v)))
+            out.write(u('</table>'))
             return out.getvalue()
         else:
             return Z3_stats_to_string(self.ctx.ref(), self.stats)
@@ -5806,7 +5834,7 @@ class Solver(Z3PPObject):
         >>> s.assert_and_track(x > 0,  'p1')
         >>> s.assert_and_track(x != 1, 'p2')
         >>> s.assert_and_track(x < 0,  p3)
-        >>> print s.check()
+        >>> print(s.check())
         unsat
         >>> c = s.unsat_core()
         >>> len(c)
@@ -5954,7 +5982,7 @@ class Solver(Z3PPObject):
     
     def help(self):
         """Display a string describing all available options."""
-        print Z3_solver_get_help(self.ctx.ref(), self.solver)
+        print(Z3_solver_get_help(self.ctx.ref(), self.solver))
 
     def param_descrs(self):
         """Return the parameter description set."""
@@ -6025,7 +6053,7 @@ class Fixedpoint(Z3PPObject):
         else:
             self.fixedpoint = fixedpoint
         Z3_fixedpoint_inc_ref(self.ctx.ref(), self.fixedpoint)
-	self.vars = []
+        self.vars = []
 
     def __del__(self):
         if self.fixedpoint != None:
@@ -6039,8 +6067,8 @@ class Fixedpoint(Z3PPObject):
 
     def help(self):
         """Display a string describing all available options."""
-        print Z3_fixedpoint_get_help(self.ctx.ref(), self.fixedpoint)
-	    
+        print(Z3_fixedpoint_get_help(self.ctx.ref(), self.fixedpoint))
+            
     def param_descrs(self):
         """Return the parameter description set."""
         return ParamDescrsRef(Z3_fixedpoint_get_param_descrs(self.ctx.ref(), self.fixedpoint), self.ctx)
@@ -6052,11 +6080,11 @@ class Fixedpoint(Z3PPObject):
         for arg in args:
             if isinstance(arg, Goal) or isinstance(arg, AstVector):
                 for f in arg:
-		    f = self.abstract(f)
+                    f = self.abstract(f)
                     Z3_fixedpoint_assert(self.ctx.ref(), self.fixedpoint, f.as_ast())
             else:
                 arg = s.cast(arg)
-		arg = self.abstract(arg)
+                arg = self.abstract(arg)
                 Z3_fixedpoint_assert(self.ctx.ref(), self.fixedpoint, arg.as_ast())
 
     def add(self, *args):
@@ -6072,38 +6100,38 @@ class Fixedpoint(Z3PPObject):
         self.assert_exprs(*args)
 
     def add_rule(self, head, body = None, name = None):
-	"""Assert rules defining recursive predicates to the fixedpoint solver.
+        """Assert rules defining recursive predicates to the fixedpoint solver.
         >>> a = Bool('a')
-	>>> b = Bool('b')
+        >>> b = Bool('b')
         >>> s = Fixedpoint()
-	>>> s.register_relation(a.decl())
-	>>> s.register_relation(b.decl())
-	>>> s.fact(a)
+        >>> s.register_relation(a.decl())
+        >>> s.register_relation(b.decl())
+        >>> s.fact(a)
         >>> s.rule(b, a)
-	>>> s.query(b)
-	sat
-	"""
-	if name == None:
-	    name = ""
+        >>> s.query(b)
+        sat
+        """
+        if name == None:
+            name = ""
         name = to_symbol(name, self.ctx)
-	if body == None:
-	    head = self.abstract(head)
-	    Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, head.as_ast(), name)	    
-	else:
-	    body = _get_args(body)
-	    f    = self.abstract(Implies(And(body),head))
-	    Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
-	
+        if body == None:
+            head = self.abstract(head)
+            Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, head.as_ast(), name)            
+        else:
+            body = _get_args(body)
+            f    = self.abstract(Implies(And(body),head))
+            Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
+        
     def rule(self, head, body = None, name = None):
-	"""Assert rules defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
-	self.add_rule(head, body, name)
-	
+        """Assert rules defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
+        self.add_rule(head, body, name)
+        
     def fact(self, head, name = None):
-	"""Assert facts defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
-	self.add_rule(head, None, name)
+        """Assert facts defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
+        self.add_rule(head, None, name)
 
     def query(self, *query):
-	"""Query the fixedpoint engine whether formula is derivable.
+        """Query the fixedpoint engine whether formula is derivable.
            You can also pass an tuple or list of recursive predicates.
         """
         query = _get_args(query)
@@ -6134,17 +6162,17 @@ class Fixedpoint(Z3PPObject):
 
     def update_rule(self, head, body, name):
         """update rule"""
-	if name == None:
-	    name = ""
+        if name == None:
+            name = ""
         name = to_symbol(name, self.ctx)
         body = _get_args(body)
         f    = self.abstract(Implies(And(body),head))
-	Z3_fixedpoint_update_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
+        Z3_fixedpoint_update_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
 
-    def get_answer(self):	
-	"""Retrieve answer from last query call."""
-	r = Z3_fixedpoint_get_answer(self.ctx.ref(), self.fixedpoint)
-	return _to_expr_ref(r, self.ctx)
+    def get_answer(self):       
+        """Retrieve answer from last query call."""
+        r = Z3_fixedpoint_get_answer(self.ctx.ref(), self.fixedpoint)
+        return _to_expr_ref(r, self.ctx)
 
     def get_num_levels(self, predicate):
         """Retrieve number of levels used for predicate in PDR engine"""
@@ -6160,40 +6188,40 @@ class Fixedpoint(Z3PPObject):
         Z3_fixedpoint_add_cover(self.ctx.ref(), self.fixedpoint, level, predicate.ast, property.ast)
 
     def register_relation(self, *relations):
-	"""Register relation as recursive"""
-	relations = _get_args(relations)
-	for f in relations:
-	    Z3_fixedpoint_register_relation(self.ctx.ref(), self.fixedpoint, f.ast)
+        """Register relation as recursive"""
+        relations = _get_args(relations)
+        for f in relations:
+            Z3_fixedpoint_register_relation(self.ctx.ref(), self.fixedpoint, f.ast)
 
     def set_predicate_representation(self, f, *representations):
-	"""Control how relation is represented"""
-	representations = _get_args(representations)
-	representations = map(to_symbol, representations)
-	sz = len(representations)
-	args = (Symbol * sz)()
-	for i in range(sz):
-	    args[i] = representations[i]
-	Z3_fixedpoint_set_predicate_representation(self.ctx.ref(), self.fixedpoint, f.ast, sz, args)
+        """Control how relation is represented"""
+        representations = _get_args(representations)
+        representations = [to_symbol(s) for s in representations]
+        sz = len(representations)
+        args = (Symbol * sz)()
+        for i in range(sz):
+            args[i] = representations[i]
+        Z3_fixedpoint_set_predicate_representation(self.ctx.ref(), self.fixedpoint, f.ast, sz, args)
 
     def parse_string(self, s):
-	"""Parse rules and queries from a string"""
-	return AstVector(Z3_fixedpoint_from_string(self.ctx.ref(), self.fixedpoint, s), self.ctx)
-	
+        """Parse rules and queries from a string"""
+        return AstVector(Z3_fixedpoint_from_string(self.ctx.ref(), self.fixedpoint, s), self.ctx)
+        
     def parse_file(self, f):
-	"""Parse rules and queries from a file"""
-	return AstVector(Z3_fixedpoint_from_file(self.ctx.ref(), self.fixedpoint, f), self.ctx)
+        """Parse rules and queries from a file"""
+        return AstVector(Z3_fixedpoint_from_file(self.ctx.ref(), self.fixedpoint, f), self.ctx)
 
     def get_rules(self):
-	"""retrieve rules that have been added to fixedpoint context"""
-	return AstVector(Z3_fixedpoint_get_rules(self.ctx.ref(), self.fixedpoint), self.ctx)
+        """retrieve rules that have been added to fixedpoint context"""
+        return AstVector(Z3_fixedpoint_get_rules(self.ctx.ref(), self.fixedpoint), self.ctx)
 
     def get_assertions(self):
-	"""retrieve assertions that have been added to fixedpoint context"""
-	return AstVector(Z3_fixedpoint_get_assertions(self.ctx.ref(), self.fixedpoint), self.ctx)
+        """retrieve assertions that have been added to fixedpoint context"""
+        return AstVector(Z3_fixedpoint_get_assertions(self.ctx.ref(), self.fixedpoint), self.ctx)
 
     def __repr__(self):
         """Return a formatted string with all added rules and constraints."""
-	return self.sexpr()
+        return self.sexpr()
 
     def sexpr(self):
         """Return a formatted string (in Lisp-like format) with all added constraints. We say the string is in s-expression format.        
@@ -6201,16 +6229,16 @@ class Fixedpoint(Z3PPObject):
         return Z3_fixedpoint_to_string(self.ctx.ref(), self.fixedpoint, 0, (Ast * 0)())
 
     def to_string(self, queries):
-	"""Return a formatted string (in Lisp-like format) with all added constraints.
+        """Return a formatted string (in Lisp-like format) with all added constraints.
            We say the string is in s-expression format.
-	   Include also queries.
+           Include also queries.
         """
-	args, len = _to_ast_array(queries)
+        args, len = _to_ast_array(queries)
         return Z3_fixedpoint_to_string(self.ctx.ref(), self.fixedpoint, len, args)
     
     def statistics(self):
         """Return statistics for the last `query()`.
-	"""
+        """
         return Statistics(Z3_fixedpoint_get_statistics(self.ctx.ref(), self.fixedpoint), self.ctx)
 
     def reason_unknown(self):
@@ -6219,21 +6247,21 @@ class Fixedpoint(Z3PPObject):
         return Z3_fixedpoint_get_reason_unknown(self.ctx.ref(), self.fixedpoint)
 
     def declare_var(self, *vars):
-	"""Add variable or several variables.
-	The added variable or variables will be bound in the rules
-	and queries
-	"""
-	vars = _get_args(vars)
-	for v in vars:
-	    self.vars += [v]
-	
+        """Add variable or several variables.
+        The added variable or variables will be bound in the rules
+        and queries
+        """
+        vars = _get_args(vars)
+        for v in vars:
+            self.vars += [v]
+        
     def abstract(self, fml, is_forall=True):
-	if self.vars == []:
-	    return fml
-	if is_forall:
-	    return ForAll(self.vars, fml)
-	else:
-	    return Exists(self.vars, fml)
+        if self.vars == []:
+            return fml
+        if is_forall:
+            return ForAll(self.vars, fml)
+        else:
+            return Exists(self.vars, fml)
 
 #########################################
 #
@@ -6425,7 +6453,7 @@ class Tactic:
 
     def help(self):
         """Display a string containing a description of the available options for the `self` tactic."""
-        print Z3_tactic_get_help(self.ctx.ref(), self.tactic)
+        print(Z3_tactic_get_help(self.ctx.ref(), self.tactic))
 
     def param_descrs(self):
         """Return the parameter description set."""
@@ -6521,7 +6549,7 @@ def ParOr(*ts, **ks):
     if __debug__:
         _z3_assert(len(ts) >= 2, "At least two arguments expected")
     ctx = _get_ctx(ks.get('ctx', None))
-    ts  = map(lambda t: _to_tactic(t, ctx), ts)
+    ts  = [ _to_tactic(t, ctx) for t in ts ]
     sz  = len(ts)
     _args = (TacticObj * sz)()
     for i in range(sz):
@@ -6566,7 +6594,7 @@ def Repeat(t, max=4294967295, ctx=None):
     >>> c = And(Or(x == 0, x == 1), Or(y == 0, y == 1), x > y)
     >>> t = Repeat(OrElse(Tactic('split-clause'), Tactic('skip')))
     >>> r = t(c)
-    >>> for subgoal in r: print subgoal
+    >>> for subgoal in r: print(subgoal)
     [x == 0, y == 0, x > y]
     [x == 0, y == 1, x > y]
     [x == 1, y == 0, x > y]
@@ -6608,19 +6636,19 @@ def describe_tactics():
     """Display a (tabular) description of all available tactics in Z3."""
     if in_html_mode():
         even = True
-        print '<table border="1" cellpadding="2" cellspacing="0">'
+        print('<table border="1" cellpadding="2" cellspacing="0">')
         for t in tactics():
             if even:
-                print '<tr style="background-color:#CFCFCF">'
+                print('<tr style="background-color:#CFCFCF">')
                 even = False
             else:
-                print '<tr>'
+                print('<tr>')
                 even = True
-            print '<td>%s</td><td>%s</td></tr>' % (t, insert_line_breaks(tactic_description(t), 40))
-        print '</table>'
+            print('<td>%s</td><td>%s</td></tr>' % (t, insert_line_breaks(tactic_description(t), 40)))
+        print('</table>')
     else:
         for t in tactics():
-            print '%s : %s' % (t, tactic_description(t))
+            print('%s : %s' % (t, tactic_description(t)))
 
 class Probe:
     """Probes are used to inspect a goal (aka problem) and collect information that may be used to decide which solver and/or preprocessing step will be used."""
@@ -6631,7 +6659,7 @@ class Probe:
             self.probe = probe
         elif isinstance(probe, float):
             self.probe = Z3_probe_const(self.ctx.ref(), probe)
-        elif isinstance(probe, int) or isinstance(probe, long):
+        elif _is_int(probe):
             self.probe = Z3_probe_const(self.ctx.ref(), float(probe))
         elif isinstance(probe, bool):
             if probe:
@@ -6796,19 +6824,19 @@ def describe_probes():
     """Display a (tabular) description of all available probes in Z3."""
     if in_html_mode():
         even = True
-        print '<table border="1" cellpadding="2" cellspacing="0">'
+        print('<table border="1" cellpadding="2" cellspacing="0">')
         for p in probes():
             if even:
-                print '<tr style="background-color:#CFCFCF">'
+                print('<tr style="background-color:#CFCFCF">')
                 even = False
             else:
-                print '<tr>'
+                print('<tr>')
                 even = True
-            print '<td>%s</td><td>%s</td></tr>' % (p, insert_line_breaks(probe_description(p), 40))
-        print '</table>'
+            print('<td>%s</td><td>%s</td></tr>' % (p, insert_line_breaks(probe_description(p), 40)))
+        print('</table>')
     else:
         for p in probes():
-            print '%s : %s' % (p, probe_description(p))
+            print('%s : %s' % (p, probe_description(p)))
 
 def _probe_nary(f, args, ctx):
     if __debug__:
@@ -6904,7 +6932,7 @@ def simplify(a, *arguments, **keywords):
 
 def help_simplify():
     """Return a string describing all options available for Z3 `simplify` procedure."""
-    print Z3_simplify_get_help(main_ctx().ref())
+    print(Z3_simplify_get_help(main_ctx().ref()))
 
 def simplify_param_descrs():
     """Return the set of parameter descriptions for Z3 `simplify` procedure."""
@@ -6927,7 +6955,7 @@ def substitute(t, *m):
             m = _get_args(m1)
     if __debug__:
         _z3_assert(is_expr(t), "Z3 expression expected")
-        _z3_assert(all(map(lambda p: isinstance(p, tuple) and is_expr(p[0]) and is_expr(p[1]) and p[0].sort().eq(p[1].sort()), m)), "Z3 invalid substitution, expression pairs expected.")
+        _z3_assert(all([isinstance(p, tuple) and is_expr(p[0]) and is_expr(p[1]) and p[0].sort().eq(p[1].sort()) for p in m]), "Z3 invalid substitution, expression pairs expected.")
     num = len(m)
     _from = (Ast * num)()
     _to   = (Ast * num)()
@@ -6949,7 +6977,7 @@ def substitute_vars(t, *m):
     """
     if __debug__:
         _z3_assert(is_expr(t), "Z3 expression expected")
-        _z3_assert(all(map(is_expr, m)), "Z3 invalid substitution, list of expressions expected.")
+        _z3_assert(all([is_expr(n) for n in m]), "Z3 invalid substitution, list of expressions expected.")
     num = len(m)
     _to   = (Ast * num)()
     for i in range(num):
@@ -6976,7 +7004,7 @@ def Sum(*args):
         _z3_assert(ctx != None, "At least one of the arguments must be a Z3 expression")
     args  = _coerce_expr_list(args, ctx)
     if is_bv(args[0]):
-        return reduce(lambda a, b: a + b, args, 0)
+        return _reduce(lambda a, b: a + b, args, 0)
     else:
         _args, sz = _to_ast_array(args)
         return ArithRef(Z3_mk_add(ctx.ref(), sz, _args), ctx)
@@ -7001,7 +7029,7 @@ def Product(*args):
         _z3_assert(ctx != None, "At least one of the arguments must be a Z3 expression")
     args  = _coerce_expr_list(args, ctx)
     if is_bv(args[0]):
-        return reduce(lambda a, b: a * b, args, 1)
+        return _reduce(lambda a, b: a * b, args, 1)
     else:
         _args, sz = _to_ast_array(args)
         return ArithRef(Z3_mk_mul(ctx.ref(), sz, _args), ctx)
@@ -7021,18 +7049,18 @@ def solve(*args, **keywords):
     s.set(**keywords)
     s.add(*args)
     if keywords.get('show', False):
-        print s
+        print(s)
     r = s.check()
     if r == unsat:
-        print "no solution"
+        print("no solution")
     elif r == unknown:
-        print "failed to solve"
+        print("failed to solve")
         try:
-            print s.model()
+            print(s.model())
         except Z3Exception:
             return
     else:
-        print s.model()
+        print(s.model())
 
 def solve_using(s, *args, **keywords):
     """Solve the constraints `*args` using solver `s`.
@@ -7047,21 +7075,21 @@ def solve_using(s, *args, **keywords):
     s.set(**keywords)
     s.add(*args)
     if keywords.get('show', False):
-        print "Problem:"
-        print s
+        print("Problem:")
+        print(s)
     r = s.check()
     if r == unsat:
-        print "no solution"
+        print("no solution")
     elif r == unknown:
-        print "failed to solve"
+        print("failed to solve")
         try:
-            print s.model()
+            print(s.model())
         except Z3Exception:
             return
     else:
         if keywords.get('show', False):
-            print "Solution:"
-        print s.model()
+            print("Solution:")
+        print(s.model())
 
 def prove(claim, **keywords):
     """Try to prove the given claim.
@@ -7079,16 +7107,16 @@ def prove(claim, **keywords):
     s.set(**keywords)
     s.add(Not(claim))
     if keywords.get('show', False):
-        print s
+        print(s)
     r = s.check()
     if r == unsat:
-        print "proved"
+        print("proved")
     elif r == unknown:
-        print "failed to prove"
-        print s.model()
+        print("failed to prove")
+        print(s.model())
     else:
-        print "counterexample"
-        print s.model()
+        print("counterexample")
+        print(s.model())
 
 def _solve_html(*args, **keywords):
     """Version of funcion `solve` used in RiSE4Fun."""
@@ -7096,21 +7124,21 @@ def _solve_html(*args, **keywords):
     s.set(**keywords)
     s.add(*args)
     if keywords.get('show', False):
-        print "<b>Problem:</b>"
-        print s
+        print("<b>Problem:</b>")
+        print(s)
     r = s.check()
     if r == unsat:
-        print "<b>no solution</b>"
+        print("<b>no solution</b>")
     elif r == unknown:
-        print "<b>failed to solve</b>"
+        print("<b>failed to solve</b>")
         try:
-            print s.model()
+            print(s.model())
         except Z3Exception:
             return
     else:
         if keywords.get('show', False):
-            print "<b>Solution:</b>"
-        print s.model()
+            print("<b>Solution:</b>")
+        print(s.model())
 
 def _solve_using_html(s, *args, **keywords):
     """Version of funcion `solve_using` used in RiSE4Fun."""
@@ -7119,21 +7147,21 @@ def _solve_using_html(s, *args, **keywords):
     s.set(**keywords)
     s.add(*args)
     if keywords.get('show', False):
-        print "<b>Problem:</b>"
-        print s
+        print("<b>Problem:</b>")
+        print(s)
     r = s.check()
     if r == unsat:
-        print "<b>no solution</b>"
+        print("<b>no solution</b>")
     elif r == unknown:
-        print "<b>failed to solve</b>"
+        print("<b>failed to solve</b>")
         try:
-            print s.model()
+            print(s.model())
         except Z3Exception:
             return
     else:
         if keywords.get('show', False):
-            print "<b>Solution:</b>"
-        print s.model()
+            print("<b>Solution:</b>")
+        print(s.model())
 
 def _prove_html(claim, **keywords):
     """Version of funcion `prove` used in RiSE4Fun."""
@@ -7143,23 +7171,24 @@ def _prove_html(claim, **keywords):
     s.set(**keywords)
     s.add(Not(claim))
     if keywords.get('show', False):
-        print s
+        print(s)
     r = s.check()
     if r == unsat:
-        print "<b>proved</b>"
+        print("<b>proved</b>")
     elif r == unknown:
-        print "<b>failed to prove</b>"
-        print s.model()
+        print("<b>failed to prove</b>")
+        print(s.model())
     else:
-        print "<b>counterexample</b>"
-        print s.model()
+        print("<b>counterexample</b>")
+        print(s.model())
 
 def _dict2sarray(sorts, ctx):
     sz = len(sorts)
     _names = (Symbol * sz)()
     _sorts = (Sort * sz) ()
     i = 0
-    for k, v in sorts.iteritems():
+    for k in sorts:
+        v = sorts[k]
         if __debug__:
             _z3_assert(isinstance(k, str), "String expected")
             _z3_assert(is_sort(v), "Z3 sort expected")
@@ -7173,7 +7202,8 @@ def _dict2darray(decls, ctx):
     _names = (Symbol * sz)()
     _decls = (FuncDecl * sz) ()
     i = 0
-    for k, v in decls.iteritems():
+    for k in decls:
+        v = decls[k]
         if __debug__:
             _z3_assert(isinstance(k, str), "String expected")
             _z3_assert(is_func_decl(v) or is_const(v), "Z3 declaration or constant expected")
diff --git a/src/api/python/z3printer.py b/src/api/python/z3printer.py
index 920de1a3b..d3dc43d3e 100644
--- a/src/api/python/z3printer.py
+++ b/src/api/python/z3printer.py
@@ -74,6 +74,15 @@ def _is_add(k):
 def _is_sub(k):
     return k == Z3_OP_SUB or k == Z3_OP_BSUB
 
+import sys
+if sys.version < '3':
+    import codecs
+    def u(x):
+        return codecs.unicode_escape_decode(x)[0]
+else:
+    def u(x):
+        return x
+
 _z3_infix_compact = [ Z3_OP_MUL, Z3_OP_BMUL, Z3_OP_POWER, Z3_OP_DIV, Z3_OP_IDIV, Z3_OP_MOD, Z3_OP_BSDIV, Z3_OP_BSMOD ]
 
 _ellipses = '...'
@@ -161,15 +170,19 @@ def _get_precedence(k):
     return _z3_precedence.get(k, 100000)
 
 _z3_html_op_to_str = {}
-for _k, _v in _z3_op_to_str.iteritems():
+for _k in _z3_op_to_str:
+    _v = _z3_op_to_str[_k]
     _z3_html_op_to_str[_k] = _v
-for _k, _v in _z3_pre_html_op_to_str.iteritems():
+for _k in _z3_pre_html_op_to_str:
+    _v = _z3_pre_html_op_to_str[_k]
     _z3_html_op_to_str[_k] = _v
 
 _z3_html_precedence = {}
-for _k, _v in _z3_precedence.iteritems():
+for _k in _z3_precedence:
+    _v = _z3_precedence[_k]
     _z3_html_precedence[_k] = _v
-for _k, _v in _z3_pre_html_precedence.iteritems():
+for _k in _z3_pre_html_precedence:
+    _v = _z3_pre_html_precedence[_k]
     _z3_html_precedence[_k] = _v
 
 _html_infix_map = {}
@@ -237,7 +250,7 @@ class FormatObject:
 
 class NAryFormatObject(FormatObject):
     def __init__(self, fs):
-        assert all(map(lambda a: isinstance(a, FormatObject), fs))
+        assert all([isinstance(a, FormatObject) for a in fs])
         self.children = fs
     def children(self):
         return self.children
@@ -246,7 +259,7 @@ class ComposeFormatObject(NAryFormatObject):
     def is_compose(sef):
         return True
     def as_tuple(self):
-        return ('compose', map(lambda a: a.as_tuple(), self.children))
+        return ('compose', [ a.as_tuple() for a in self.children ])
     def space_upto_nl(self):
         r = 0
         for child in self.children:
@@ -256,13 +269,13 @@ class ComposeFormatObject(NAryFormatObject):
                 return (r, True)
         return (r, False)
     def flat(self):
-        return compose(map(lambda a: a.flat(), self.children))
+        return compose([a.flat() for a in self.children ])
 
 class ChoiceFormatObject(NAryFormatObject):
     def is_choice(sef):
         return True
     def as_tuple(self):
-        return ('choice', map(lambda a: a.as_tuple(), self.children))
+        return ('choice', [ a.as_tuple() for a in self.children ])
     def space_upto_nl(self):
         return self.children[0].space_upto_nl()
     def flat(self):
@@ -388,11 +401,11 @@ class PP:
         if not self.bounded or self.pos <= self.max_width:
             sz = _len(f)
             if self.bounded and self.pos + sz > self.max_width:
-                self.out.write(_ellipses)
+                self.out.write(u(_ellipses))
             else:
                 self.pos = self.pos + sz
                 self.ribbon_pos = self.ribbon_pos + sz
-                self.out.write(unicode(f.string))
+                self.out.write(u(f.string))
 
     def pp_compose(self, f, indent):
         for c in f.children:
@@ -410,11 +423,11 @@ class PP:
         self.ribbon_pos = 0
         self.line = self.line + 1
         if self.line < self.max_lines: 
-            self.out.write(unicode('\n'))
+            self.out.write(u('\n'))
             for i in range(indent):
-                self.out.write(unicode(' '))
+                self.out.write(u(' '))
         else:
-            self.out.write(unicode('\n...'))
+            self.out.write(u('\n...'))
             raise StopPPException()
 
     def pp(self, f, indent):
@@ -791,7 +804,11 @@ class Formatter:
                 r.append(self.pp_ellipses())
                 break
         if sz <= self.max_args:
-            else_pp = self.pp_expr(f.else_value(), 0, [])
+            else_val = f.else_value()
+            if else_val == None:
+                else_pp  = to_format('#unspecified')
+            else:
+                else_pp  = self.pp_expr(else_val, 0, [])
             r.append(group(seq((to_format('else'), else_pp), self.pp_arrow())))
         return seq3(r, '[', ']')
 
@@ -953,23 +970,23 @@ def in_html_mode():
 
 def pp(a):
     if _support_pp(a):
-        print obj_to_string(a)
+        print(obj_to_string(a))
     else:
-        print a
+        print(a)
 
 def print_matrix(m):
     z3._z3_assert(isinstance(m, list) or isinstance(m, tuple), "matrix expected")
     if not in_html_mode():
-        print obj_to_string(m)
+        print(obj_to_string(m))
     else:
-        print '<table cellpadding="2", cellspacing="0", border="1">'
+        print('<table cellpadding="2", cellspacing="0", border="1">')
         for r in m:
             z3._z3_assert(isinstance(r, list) or isinstance(r, tuple), "matrix expected")
-            print '<tr>'
+            print('<tr>')
             for c in r:
-                print '<td>%s</td>' % c
-            print '</tr>'
-        print '</table>'
+                print('<td>%s</td>' % c)
+            print('</tr>')
+        print('</table>')
     
 def insert_line_breaks(s, width):
     """Break s in lines of size width (approx)"""
@@ -980,9 +997,9 @@ def insert_line_breaks(s, width):
     w = 0
     for i in range(sz):
         if w > width and s[i] == ' ':
-            new_str.write(u'<br />')
+            new_str.write(u('<br />'))
             w = 0
         else:
-            new_str.write(unicode(s[i]))
+            new_str.write(u(s[i]))
         w = w + 1
     return new_str.getvalue()
diff --git a/src/api/z3_api.h b/src/api/z3_api.h
index 49d59e125..98bde7bcf 100644
--- a/src/api/z3_api.h
+++ b/src/api/z3_api.h
@@ -1080,6 +1080,7 @@ typedef enum {
     Z3_PK_INVALID
 } Z3_param_kind;
 
+#ifdef CorML3
 /**
    \mlonly {!search_failure} \endmlonly \conly \brief
    The different kinds of search failure types.
@@ -1103,6 +1104,7 @@ typedef enum {
     Z3_THEORY,        
     Z3_QUANTIFIERS
 } Z3_search_failure;
+#endif
 
 /**
    \mlonly {!ast_print_mode} \endmlonly \conly \brief
@@ -6922,12 +6924,15 @@ END_MLAPI_EXCLUDE
         );
 
     /*@}*/
-    
+#endif
+
+
     /**
        @name Deprecated Constraints API
     */
     /*@{*/
 
+#ifdef CorML3
     /**
        \brief Set the SMTLIB logic to be used in the given logical context.
        It is incorrect to invoke this function after invoking
@@ -7109,7 +7114,9 @@ END_MLAPI_EXCLUDE
         __out Z3_model * m, __out Z3_ast* proof, 
         __inout unsigned* core_size, __inout_ecount(num_assumptions) Z3_ast core[]
         );
+#endif
 
+#ifdef CorML4
     /**
        \brief Retrieve congruence class representatives for terms.
 
@@ -7123,23 +7130,26 @@ END_MLAPI_EXCLUDE
        This means that two terms map to the same class identifier if and only if
        the current context implies that they are equal.
 
-       A side-effect of the function is a satisfiability check.
+       A side-effect of the function is a satisfiability check on the assertions on the solver that is passed in.
        The function return Z3_L_FALSE if the current assertions are not satisfiable.
 
        \sa Z3_check_and_get_model
        \sa Z3_check
     
-       \deprecated Subsumed by Z3_solver API
+       \deprecated To be moved outside of API.
 
-       def_API('Z3_get_implied_equalities', UINT, (_in(CONTEXT), _in(UINT), _in_array(1, AST), _out_array(1, UINT)))
+       def_API('Z3_get_implied_equalities', UINT, (_in(CONTEXT), _in(SOLVER), _in(UINT), _in_array(2, AST), _out_array(2, UINT)))
     */
     Z3_lbool Z3_API Z3_get_implied_equalities(
         __in Z3_context c, 
+        __in Z3_solver  s, 
         __in unsigned num_terms,
         __in_ecount(num_terms) Z3_ast const terms[],
         __out_ecount(num_terms) unsigned class_ids[]
         );
+#endif
 
+#ifdef CorML3
     /**
        \brief Delete a model object.
        
diff --git a/src/api/z3_private.h b/src/api/z3_private.h
index 17075a6c6..91becd158 100644
--- a/src/api/z3_private.h
+++ b/src/api/z3_private.h
@@ -36,38 +36,6 @@ extern "C" {
 
     Z3_bool Z3_API Z3_get_numeral_rational(__in Z3_context c, __in Z3_ast a, rational& r);
 
-    /**
-       \brief \mlh exec_smtlib2_string c str \endmlh
-       Parse the given string using the SMT-LIB2 parser and execute its commands.
-              
-       It returns a formula comprising of the conjunction of assertions in the scope
-       (up to push/pop) at the end of the string.
-       The returned formula is also asserted to the logical context on return.
-     */
-    Z3_ast Z3_API Z3_exec_smtlib2_string(__in Z3_context c, 
-                                         __in Z3_string str,
-                                         __in unsigned num_sorts,
-                                         __in_ecount(num_sorts) Z3_symbol sort_names[],
-                                         __in_ecount(num_sorts) Z3_sort sorts[],
-                                         __in unsigned num_decls,
-                                         __in_ecount(num_decls) Z3_symbol decl_names[],
-                                         __in_ecount(num_decls) Z3_func_decl decls[]  
-                                         );
-    
-    /**
-       \brief Similar to #Z3_exec_smtlib2_string, but reads the commands from a file.
-    */
-    Z3_ast Z3_API Z3_exec_smtlib2_file(__in Z3_context c, 
-                                       __in Z3_string file_name,
-                                          __in unsigned num_sorts,
-                                          __in_ecount(num_sorts) Z3_symbol sort_names[],
-                                          __in_ecount(num_sorts) Z3_sort sorts[],
-                                          __in unsigned num_decls,
-                                          __in_ecount(num_decls) Z3_symbol decl_names[],
-                                          __in_ecount(num_decls) Z3_func_decl decls[]  
-                                       );
-
-
 #ifndef CAMLIDL
 #ifdef __cplusplus
 };
diff --git a/src/ast/arith_decl_plugin.cpp b/src/ast/arith_decl_plugin.cpp
index a89cc18d0..f2dccf065 100644
--- a/src/ast/arith_decl_plugin.cpp
+++ b/src/ast/arith_decl_plugin.cpp
@@ -573,18 +573,7 @@ expr * arith_decl_plugin::get_some_value(sort * s) {
     return mk_numeral(rational(0), s == m_int_decl);
 }
 
-arith_util::arith_util(ast_manager & m):
-    m_manager(m),
-    m_afid(m.get_family_id("arith")),
-    m_plugin(0) {
-}
-
-void arith_util::init_plugin() {
-    SASSERT(m_plugin == 0);
-    m_plugin = static_cast<arith_decl_plugin*>(m_manager.get_plugin(m_afid));
-}
-
-bool arith_util::is_numeral(expr const * n, rational & val, bool & is_int) const {
+bool arith_recognizers::is_numeral(expr const * n, rational & val, bool & is_int) const {
     if (!is_app_of(n, m_afid, OP_NUM))
         return false;
     func_decl * decl = to_app(n)->get_decl();
@@ -593,6 +582,17 @@ bool arith_util::is_numeral(expr const * n, rational & val, bool & is_int) const
     return true;
 }
 
+arith_util::arith_util(ast_manager & m):
+    arith_recognizers(m.mk_family_id("arith")),
+    m_manager(m),
+    m_plugin(0) {
+}
+
+void arith_util::init_plugin() {
+    SASSERT(m_plugin == 0);
+    m_plugin = static_cast<arith_decl_plugin*>(m_manager.get_plugin(m_afid));
+}
+
 bool arith_util::is_irrational_algebraic_numeral(expr const * n, algebraic_numbers::anum & val) {
     if (!is_app_of(n, m_afid, OP_IRRATIONAL_ALGEBRAIC_NUM))
         return false;
diff --git a/src/ast/arith_decl_plugin.h b/src/ast/arith_decl_plugin.h
index c39768d4c..e63e866c3 100644
--- a/src/ast/arith_decl_plugin.h
+++ b/src/ast/arith_decl_plugin.h
@@ -187,36 +187,24 @@ public:
     virtual void set_cancel(bool f);
 };
 
-class arith_util {
-    ast_manager &       m_manager;
+/**
+   \brief Procedures for recognizing arithmetic expressions.
+   We don't need access to ast_manager, and operations can be simultaneously
+   executed in different threads.
+*/
+class arith_recognizers {
+protected:
     family_id           m_afid;
-    arith_decl_plugin * m_plugin;
-
-    void init_plugin();
-
-    arith_decl_plugin & plugin() const {
-        if (!m_plugin) const_cast<arith_util*>(this)->init_plugin();
-        SASSERT(m_plugin != 0);
-        return *m_plugin;
-    }
-    
 public:
-    arith_util(ast_manager & m);
+    arith_recognizers(family_id id):m_afid(id) {}
 
-    ast_manager & get_manager() const { return m_manager; }
     family_id get_family_id() const { return m_afid; }
 
-    algebraic_numbers::manager & am() { 
-        return plugin().am(); 
-    }
-
     bool is_arith_expr(expr const * n) const { return is_app(n) && to_app(n)->get_family_id() == m_afid; }
+    bool is_irrational_algebraic_numeral(expr const * n) const { return is_app_of(n, m_afid, OP_IRRATIONAL_ALGEBRAIC_NUM); }
     bool is_numeral(expr const * n, rational & val, bool & is_int) const;
     bool is_numeral(expr const * n, rational & val) const { bool is_int; return is_numeral(n, val, is_int); }
     bool is_numeral(expr const * n) const { return is_app_of(n, m_afid, OP_NUM); }
-    bool is_irrational_algebraic_numeral(expr const * n) const { return is_app_of(n, m_afid, OP_IRRATIONAL_ALGEBRAIC_NUM); }
-    bool is_irrational_algebraic_numeral(expr const * n, algebraic_numbers::anum & val);
-    algebraic_numbers::anum const & to_irrational_algebraic_numeral(expr const * n);
     bool is_zero(expr const * n) const { rational val; return is_numeral(n, val) && val.is_zero(); }
     bool is_minus_one(expr * n) const { rational tmp; return is_numeral(n, tmp) && tmp.is_minus_one(); }
     // return true if \c n is a term of the form (* -1 r)
@@ -227,6 +215,7 @@ public:
         }
         return false;
     }
+
     bool is_le(expr const * n) const { return is_app_of(n, m_afid, OP_LE); }
     bool is_ge(expr const * n) const { return is_app_of(n, m_afid, OP_GE); }
     bool is_lt(expr const * n) const { return is_app_of(n, m_afid, OP_LT); }
@@ -245,14 +234,13 @@ public:
     bool is_power(expr const * n) const { return is_app_of(n, m_afid, OP_POWER); }
     
     bool is_int(sort const * s) const { return is_sort_of(s, m_afid, INT_SORT); }
-    bool is_int(expr const * n) const { return is_int(m_manager.get_sort(n)); }
+    bool is_int(expr const * n) const { return is_int(get_sort(n)); }
     bool is_real(sort const * s) const { return is_sort_of(s, m_afid, REAL_SORT); }
-    bool is_real(expr const * n) const { return is_real(m_manager.get_sort(n)); }
+    bool is_real(expr const * n) const { return is_real(get_sort(n)); }
     bool is_int_real(sort const * s) const { return s->get_family_id() == m_afid; }
-    bool is_int_real(expr const * n) const { return is_int_real(m_manager.get_sort(n)); }
+    bool is_int_real(expr const * n) const { return is_int_real(get_sort(n)); }
 
     MATCH_UNARY(is_uminus);
-
     MATCH_BINARY(is_sub);
     MATCH_BINARY(is_add);
     MATCH_BINARY(is_mul);
@@ -265,6 +253,34 @@ public:
     MATCH_BINARY(is_div);
     MATCH_BINARY(is_idiv);
 
+    bool is_pi(expr * arg) { return is_app_of(arg, m_afid, OP_PI); }
+    bool is_e(expr * arg) { return is_app_of(arg, m_afid, OP_E); }
+};
+
+class arith_util : public arith_recognizers {
+    ast_manager &       m_manager;
+    arith_decl_plugin * m_plugin;
+
+    void init_plugin();
+
+    arith_decl_plugin & plugin() const {
+        if (!m_plugin) const_cast<arith_util*>(this)->init_plugin();
+        SASSERT(m_plugin != 0);
+        return *m_plugin;
+    }
+    
+public:
+    arith_util(ast_manager & m);
+
+    ast_manager & get_manager() const { return m_manager; }
+
+    algebraic_numbers::manager & am() { 
+        return plugin().am(); 
+    }
+
+    bool is_irrational_algebraic_numeral(expr const * n) const { return is_app_of(n, m_afid, OP_IRRATIONAL_ALGEBRAIC_NUM); }
+    bool is_irrational_algebraic_numeral(expr const * n, algebraic_numbers::anum & val);
+    algebraic_numbers::anum const & to_irrational_algebraic_numeral(expr const * n);
     
     sort * mk_int() { return m_manager.mk_sort(m_afid, INT_SORT); }
     sort * mk_real() { return m_manager.mk_sort(m_afid, REAL_SORT); }
@@ -320,9 +336,6 @@ public:
     app * mk_acosh(expr * arg) { return m_manager.mk_app(m_afid, OP_ACOSH, arg); }
     app * mk_atanh(expr * arg) { return m_manager.mk_app(m_afid, OP_ATANH, arg); }
 
-    bool is_pi(expr * arg) { return is_app_of(arg, m_afid, OP_PI); }
-    bool is_e(expr * arg) { return is_app_of(arg, m_afid, OP_E); }
-
     app * mk_pi() { return plugin().mk_pi(); }
     app * mk_e()  { return plugin().mk_e(); }
 
diff --git a/src/ast/array_decl_plugin.cpp b/src/ast/array_decl_plugin.cpp
index 23d5145ea..857cec105 100644
--- a/src/ast/array_decl_plugin.cpp
+++ b/src/ast/array_decl_plugin.cpp
@@ -542,6 +542,16 @@ bool array_decl_plugin::is_fully_interp(sort const * s) const {
     return m_manager->is_fully_interp(get_array_range(s));
 }
 
+func_decl * array_recognizers::get_as_array_func_decl(app * n) const { 
+    SASSERT(is_as_array(n)); 
+    return to_func_decl(n->get_decl()->get_parameter(0).get_ast()); 
+}
+
+array_util::array_util(ast_manager& m): 
+    array_recognizers(m.mk_family_id("array")),
+    m_manager(m) {
+}
+
 bool array_util::is_as_array_tree(expr * n) {
     ptr_buffer<expr, 32> todo;
     todo.push_back(n);
diff --git a/src/ast/array_decl_plugin.h b/src/ast/array_decl_plugin.h
index 68c473560..2184b0088 100644
--- a/src/ast/array_decl_plugin.h
+++ b/src/ast/array_decl_plugin.h
@@ -129,27 +129,34 @@ class array_decl_plugin : public decl_plugin {
     virtual bool is_fully_interp(sort const * s) const;
 };
 
-class array_util {
-    ast_manager & m_manager;
-    family_id    m_fid;
+class array_recognizers {
+protected:
+    family_id m_fid;
 public:
-    array_util(ast_manager& m): m_manager(m), m_fid(m.get_family_id("array")) {}
-    ast_manager & get_manager() const { return m_manager; }
+    array_recognizers(family_id fid):m_fid(fid) {}
     family_id get_family_id() const { return m_fid; }
     bool is_array(sort* s) const { return is_sort_of(s, m_fid, ARRAY_SORT);}
-    bool is_array(expr* n) const { return is_array(m_manager.get_sort(n)); }
+    bool is_array(expr* n) const { return is_array(get_sort(n)); }
     bool is_select(expr* n) const { return is_app_of(n, m_fid, OP_SELECT); }
     bool is_store(expr* n) const { return is_app_of(n, m_fid, OP_STORE); }
     bool is_const(expr* n) const { return is_app_of(n, m_fid, OP_CONST_ARRAY); }
     bool is_map(expr* n) const { return is_app_of(n, m_fid, OP_ARRAY_MAP); }
     bool is_as_array(expr * n) const { return is_app_of(n, m_fid, OP_AS_ARRAY); }
-    bool is_as_array_tree(expr * n);
     bool is_select(func_decl* f) const { return is_decl_of(f, m_fid, OP_SELECT); }
     bool is_store(func_decl* f) const { return is_decl_of(f, m_fid, OP_STORE); }
     bool is_const(func_decl* f) const { return is_decl_of(f, m_fid, OP_CONST_ARRAY); }
     bool is_map(func_decl* f) const { return is_decl_of(f, m_fid, OP_ARRAY_MAP); }
     bool is_as_array(func_decl* f) const { return is_decl_of(f, m_fid, OP_AS_ARRAY); }
-    func_decl * get_as_array_func_decl(app * n) const { SASSERT(is_as_array(n)); return to_func_decl(n->get_decl()->get_parameter(0).get_ast()); }
+    func_decl * get_as_array_func_decl(app * n) const;
+};
+
+class array_util : public array_recognizers {
+    ast_manager & m_manager;
+public:
+    array_util(ast_manager& m);
+    ast_manager & get_manager() const { return m_manager; }
+
+    bool is_as_array_tree(expr * n);
 
     app * mk_store(unsigned num_args, expr * const * args) {
         return m_manager.mk_app(m_fid, OP_STORE, 0, 0, num_args, args);
diff --git a/src/ast/ast.cpp b/src/ast/ast.cpp
index 3fb422a2e..486aa9646 100644
--- a/src/ast/ast.cpp
+++ b/src/ast/ast.cpp
@@ -137,7 +137,7 @@ void display_parameters(std::ostream & out, unsigned n, parameter const * p) {
 //
 // -----------------------------------
 
-family_id family_manager::get_family_id(symbol const & s) {
+family_id family_manager::mk_family_id(symbol const & s) {
     family_id r; 
     if (m_families.find(s, r)) {
         return r;
@@ -149,7 +149,15 @@ family_id family_manager::get_family_id(symbol const & s) {
     return r;
 }
 
-bool family_manager::has_family(symbol const & s) {
+family_id family_manager::get_family_id(symbol const & s) const {
+    family_id r; 
+    if (m_families.find(s, r))
+        return r;
+    else
+        return null_family_id;
+}
+
+bool family_manager::has_family(symbol const & s) const {
     return m_families.contains(s);
 }
 
@@ -374,6 +382,31 @@ quantifier::quantifier(bool forall, unsigned num_decls, sort * const * decl_sort
     memcpy(const_cast<expr **>(get_no_patterns()), no_patterns, sizeof(expr *) * num_no_patterns);
 }
 
+// -----------------------------------
+//
+// Auxiliary functions
+//
+// -----------------------------------
+
+sort * get_sort(expr const * n) {
+    while (true) {
+        switch(n->get_kind()) {
+        case AST_APP: 
+            return to_app(n)->get_decl()->get_range();
+        case AST_VAR:
+            return to_var(n)->get_sort();
+        case AST_QUANTIFIER:
+            // The sort of the quantifier is the sort of the nested expression.
+            // This code assumes the given expression is well-sorted.
+            n = to_quantifier(n)->get_expr();
+            break;
+        default:
+            UNREACHABLE();
+            return 0;
+        }
+    }
+}
+
 // -----------------------------------
 //
 // AST hash-consing
@@ -1048,6 +1081,16 @@ expr * basic_decl_plugin::get_some_value(sort * s) {
     return 0;
 }
 
+bool basic_recognizers::is_ite(expr const * n, expr * & t1, expr * & t2, expr * & t3) const { 
+    if (is_ite(n)) { 
+        t1 = to_app(n)->get_arg(0); 
+        t2 = to_app(n)->get_arg(1); 
+        t3 = to_app(n)->get_arg(2);
+        return true; 
+    } 
+    return false; 
+}
+
 // -----------------------------------
 //
 // label_decl_plugin 
@@ -1262,12 +1305,12 @@ void ast_manager::init() {
     m_expr_id_gen.reset(0);
     m_decl_id_gen.reset(c_first_decl_id);
     m_some_value_proc = 0;
-    m_basic_family_id          = get_family_id("basic");
-    m_label_family_id          = get_family_id("label");
-    m_pattern_family_id        = get_family_id("pattern");
-    m_model_value_family_id    = get_family_id("model-value");
-    m_user_sort_family_id      = get_family_id("user-sort");
-    m_arith_family_id          = get_family_id("arith");
+    m_basic_family_id          = mk_family_id("basic");
+    m_label_family_id          = mk_family_id("label");
+    m_pattern_family_id        = mk_family_id("pattern");
+    m_model_value_family_id    = mk_family_id("model-value");
+    m_user_sort_family_id      = mk_family_id("user-sort");
+    m_arith_family_id          = mk_family_id("arith");
     basic_decl_plugin * plugin = alloc(basic_decl_plugin);
     register_plugin(m_basic_family_id, plugin);
     m_bool_sort = plugin->mk_bool_sort();
@@ -1400,7 +1443,7 @@ void ast_manager::copy_families_plugins(ast_manager const & from) {
             << ", target has_family: " << m_family_manager.has_family(fid) << "\n";
             if (m_family_manager.has_family(fid)) tout << get_family_id(fid_name) << "\n";);
       if (!m_family_manager.has_family(fid)) {
-          family_id new_fid = get_family_id(fid_name);          
+          family_id new_fid = mk_family_id(fid_name);          
           TRACE("copy_families_plugins", tout << "new target fid created: " << new_fid << " fid_name: " << fid_name << "\n";);
       }
       TRACE("copy_families_plugins", tout << "target fid: " << get_family_id(fid_name) << "\n";);
@@ -1437,7 +1480,7 @@ void ast_manager::set_next_expr_id(unsigned id) {
 unsigned ast_manager::get_node_size(ast const * n) { return ::get_node_size(n); }
 
 void ast_manager::register_plugin(symbol const & s, decl_plugin * plugin) {
-    family_id id = m_family_manager.get_family_id(s);
+    family_id id = m_family_manager.mk_family_id(s);
     SASSERT(is_format_manager() || s != symbol("format"));
     register_plugin(id, plugin);
 }
@@ -1495,20 +1538,6 @@ void ast_manager::register_plugin(family_id id, decl_plugin * plugin) {
     plugin->set_manager(this, id);
 }
 
-sort * ast_manager::get_sort(expr const * n) const {
-    switch(n->get_kind()) {
-    case AST_APP: 
-        return to_app(n)->get_decl()->get_range();
-    case AST_VAR:
-        return to_var(n)->get_sort();
-    case AST_QUANTIFIER:
-        return m_bool_sort;
-    default:
-        UNREACHABLE();
-        return 0;
-    }
-}
-
 bool ast_manager::is_bool(expr const * n) const {
     return get_sort(n) == m_bool_sort;
 }
diff --git a/src/ast/ast.h b/src/ast/ast.h
index e9da41377..3f03b86b9 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -188,10 +188,20 @@ class family_manager {
     svector<symbol>         m_names;
 public:
     family_manager():m_next_id(0) {}
+
+    /**
+       \brief Return the family_id for s, a new id is created if !has_family(s)
+       
+       If has_family(s), then this method is equivalent to get_family_id(s)
+    */
+    family_id mk_family_id(symbol const & s);
+
+    /**
+       \brief Return the family_id for s, return null_family_id if s was not registered in the manager.
+    */
+    family_id get_family_id(symbol const & s) const;
     
-    family_id get_family_id(symbol const & s);
-    
-    bool has_family(symbol const & s);
+    bool has_family(symbol const & s) const;
 
     void get_dom(svector<symbol>& dom) const { m_families.get_dom(dom); }
     
@@ -1287,6 +1297,55 @@ inline bool has_labels(expr const * n) {
     else return false;
 }
 
+sort * get_sort(expr const * n);
+
+class basic_recognizers {
+    family_id m_fid;
+public:
+    basic_recognizers(family_id fid):m_fid(fid) {}
+    bool is_bool(sort const * s) const { return is_sort_of(s, m_fid, BOOL_SORT); }
+    bool is_bool(expr const * n) const { return is_bool(get_sort(n)); }
+    bool is_or(expr const * n) const { return is_app_of(n, m_fid, OP_OR); }
+    bool is_implies(expr const * n) const { return is_app_of(n, m_fid, OP_IMPLIES); }
+    bool is_and(expr const * n) const { return is_app_of(n, m_fid, OP_AND); }
+    bool is_not(expr const * n) const { return is_app_of(n, m_fid, OP_NOT); }
+    bool is_eq(expr const * n) const { return is_app_of(n, m_fid, OP_EQ); }
+    bool is_oeq(expr const * n) const { return is_app_of(n, m_fid, OP_OEQ); }
+    bool is_distinct(expr const * n) const { return is_app_of(n, m_fid, OP_DISTINCT); }
+    bool is_iff(expr const * n) const { return is_app_of(n, m_fid, OP_IFF); }
+    bool is_xor(expr const * n) const { return is_app_of(n, m_fid, OP_XOR); }
+    bool is_ite(expr const * n) const { return is_app_of(n, m_fid, OP_ITE); }
+    bool is_term_ite(expr const * n) const { return is_ite(n) && !is_bool(n); }
+    bool is_true(expr const * n) const { return is_app_of(n, m_fid, OP_TRUE); }
+    bool is_false(expr const * n) const { return is_app_of(n, m_fid, OP_FALSE); }
+    bool is_complement_core(expr const * n1, expr const * n2) const { 
+        return (is_true(n1) && is_false(n2)) || (is_not(n1) && to_app(n1)->get_arg(0) == n2);
+    }
+    bool is_complement(expr const * n1, expr const * n2) const { return is_complement_core(n1, n2) || is_complement_core(n2, n1); }
+    bool is_or(func_decl const * d) const { return is_decl_of(d, m_fid, OP_OR); }
+    bool is_implies(func_decl const * d) const { return is_decl_of(d, m_fid, OP_IMPLIES); }
+    bool is_and(func_decl const * d) const { return is_decl_of(d, m_fid, OP_AND); }
+    bool is_not(func_decl const * d) const { return is_decl_of(d, m_fid, OP_NOT); }
+    bool is_eq(func_decl const * d) const { return is_decl_of(d, m_fid, OP_EQ); }
+    bool is_iff(func_decl const * d) const { return is_decl_of(d, m_fid, OP_IFF); }
+    bool is_xor(func_decl const * d) const { return is_decl_of(d, m_fid, OP_XOR); }
+    bool is_ite(func_decl const * d) const { return is_decl_of(d, m_fid, OP_ITE); }
+    bool is_term_ite(func_decl const * d) const { return is_ite(d) && !is_bool(d->get_range()); }
+    bool is_distinct(func_decl const * d) const { return is_decl_of(d, m_fid, OP_DISTINCT); }
+
+    MATCH_UNARY(is_not);
+    MATCH_BINARY(is_eq);
+    MATCH_BINARY(is_iff);
+    MATCH_BINARY(is_implies);
+    MATCH_BINARY(is_and);
+    MATCH_BINARY(is_or);
+    MATCH_BINARY(is_xor);
+    MATCH_TERNARY(is_and);
+    MATCH_TERNARY(is_or);
+
+    bool is_ite(expr const * n, expr * & t1, expr * & t2, expr * & t3) const;
+};
+
 // -----------------------------------
 //
 // Get Some Value functor
@@ -1404,6 +1463,8 @@ public:
 
     // propagate cancellation signal to decl_plugins
     void set_cancel(bool f);
+    void cancel() { set_cancel(true); }
+    void reset_cancel() { set_cancel(false); }
 
     bool has_trace_stream() const { return m_trace_stream != 0; }
     std::ostream & trace_stream() { SASSERT(has_trace_stream()); return *m_trace_stream; }
@@ -1432,8 +1493,10 @@ public:
 
     small_object_allocator & get_allocator() { return m_alloc; }
     
-    family_id get_family_id(symbol const & s) const { return const_cast<ast_manager*>(this)->m_family_manager.get_family_id(s); }
-    
+    family_id mk_family_id(symbol const & s) { return m_family_manager.mk_family_id(s); }
+    family_id mk_family_id(char const * s) { return mk_family_id(symbol(s)); }
+
+    family_id get_family_id(symbol const & s) const { return m_family_manager.get_family_id(s); }
     family_id get_family_id(char const * s) const { return get_family_id(symbol(s)); }
 
     symbol const & get_family_name(family_id fid) const { return m_family_manager.get_name(fid); }
@@ -1456,7 +1519,7 @@ public:
     
     bool has_plugin(family_id fid) const { return get_plugin(fid) != 0; }
     
-    bool has_plugin(symbol const & s) const { return has_plugin(get_family_id(s)); }
+    bool has_plugin(symbol const & s) const { return m_family_manager.has_family(s) && has_plugin(m_family_manager.get_family_id(s)); }
     
     void get_dom(svector<symbol> & dom) const { m_family_manager.get_dom(dom); }
     
@@ -1546,7 +1609,7 @@ protected:
     }
     
 public:
-    sort * get_sort(expr const * n) const;
+    sort * get_sort(expr const * n) const { return ::get_sort(n); }
     void check_sort(func_decl const * decl, unsigned num_args, expr * const * args) const;
     void check_sorts_core(ast const * n) const;
     bool check_sorts(ast const * n) const;
diff --git a/src/ast/ast_smt2_pp.cpp b/src/ast/ast_smt2_pp.cpp
index afe301ddf..1ad2b8222 100644
--- a/src/ast/ast_smt2_pp.cpp
+++ b/src/ast/ast_smt2_pp.cpp
@@ -501,7 +501,12 @@ class smt2_printer {
     }
 
     format * pp_simple_attribute(char const * attr, symbol const & s) {
-        return mk_compose(m(), mk_string(m(), attr), mk_string(m(), s.str().c_str()));
+        std::string str;
+        if (is_smt2_quoted_symbol(s))
+            str = mk_smt2_quoted_symbol(s);
+        else
+            str = s.str();
+        return mk_compose(m(), mk_string(m(), attr), mk_string(m(), str.c_str()));
     }
 
     format * pp_labels(bool is_pos, buffer<symbol> const & names, format * f) {
@@ -851,7 +856,7 @@ class smt2_printer {
                 buf.push_back(pp_simple_attribute(":weight ", q->get_weight()));
             }
             if (q->get_skid() != symbol::null) {
-                buf.push_back(pp_simple_attribute(":skid ", q->get_skid()));
+                buf.push_back(pp_simple_attribute(":skolemid ", q->get_skid()));
             }
             if (q->get_qid() != symbol::null) {
 #if 0
diff --git a/src/ast/ast_smt_pp.cpp b/src/ast/ast_smt_pp.cpp
index 78a1caf68..66b467b92 100644
--- a/src/ast/ast_smt_pp.cpp
+++ b/src/ast/ast_smt_pp.cpp
@@ -795,11 +795,11 @@ public:
         m_simplify_implies(simplify_implies)
     {
         m_basic_fid = m.get_basic_family_id();
-        m_label_fid = m.get_family_id("label");
-        m_bv_fid    = m.get_family_id("bv");
-        m_arith_fid = m.get_family_id("arith");
-        m_array_fid = m.get_family_id("array");
-        m_dt_fid    = m.get_family_id("datatype");
+        m_label_fid = m.mk_family_id("label");
+        m_bv_fid    = m.mk_family_id("bv");
+        m_arith_fid = m.mk_family_id("arith");
+        m_array_fid = m.mk_family_id("array");
+        m_dt_fid    = m.mk_family_id("datatype");
     }
     
     void operator()(expr* n) {
@@ -1009,7 +1009,7 @@ ast_smt_pp::ast_smt_pp(ast_manager& m):
     m_status("unknown"),
     m_category(),
     m_logic(),
-    m_dt_fid(m.get_family_id("datatype")),
+    m_dt_fid(m.mk_family_id("datatype")),
     m_is_declared(&m_is_declared_default),
     m_simplify_implies(true)
 {}
diff --git a/src/ast/bv_decl_plugin.cpp b/src/ast/bv_decl_plugin.cpp
index fd15ca681..9c5bccbc6 100644
--- a/src/ast/bv_decl_plugin.cpp
+++ b/src/ast/bv_decl_plugin.cpp
@@ -41,26 +41,6 @@ bv_decl_plugin::bv_decl_plugin():
     m_int_sort(0) {
 }
 
-void bv_decl_plugin::mk_table_upto(unsigned n) {
-    if (m_powers.empty()) {
-        m_powers.push_back(rational(1));
-    }
-    unsigned sz = m_powers.size();
-    rational curr = m_powers[sz - 1];
-    rational two(2);
-    for (unsigned i = sz; i <= n; i++) {
-        curr *= two;
-        m_powers.push_back(curr);
-    }
-}
-
-rational bv_decl_plugin::power_of_two(unsigned n) const {
-    if (n >= m_powers.size()) {
-        const_cast<bv_decl_plugin*>(this)->mk_table_upto(n + 1);
-    }
-    return m_powers[n];
-}
-
 void bv_decl_plugin::set_manager(ast_manager * m, family_id id) {
     decl_plugin::set_manager(m, id);
 
@@ -79,7 +59,7 @@ void bv_decl_plugin::set_manager(ast_manager * m, family_id id) {
     m_xor3 = m_manager->mk_func_decl(symbol("xor3"), 3, d, b, func_decl_info(m_family_id, OP_XOR3));
     m_manager->inc_ref(m_xor3);
 
-    m_int_sort = m_manager->mk_sort(m_manager->get_family_id("arith"), INT_SORT);
+    m_int_sort = m_manager->mk_sort(m_manager->mk_family_id("arith"), INT_SORT);
     SASSERT(m_int_sort != 0); // arith_decl_plugin must be installed before bv_decl_plugin.
     m_manager->inc_ref(m_int_sort);
 }
@@ -169,7 +149,7 @@ void bv_decl_plugin::mk_bv_sort(unsigned bv_size) {
             sz = sort_size::mk_very_big();
         }
         else {
-            sz = sort_size(power_of_two(bv_size));
+            sz = sort_size(rational::power_of_two(bv_size));
         }
         m_bv_sorts[bv_size] = m_manager->mk_sort(symbol("bv"), sort_info(m_family_id, BV_SORT, sz, 1, &p));
         m_manager->inc_ref(m_bv_sorts[bv_size]);
@@ -436,7 +416,7 @@ func_decl * bv_decl_plugin::mk_num_decl(unsigned num_parameters, parameter const
     // This cannot be enforced now, since some Z3 modules try to generate these invalid numerals.
     // After SMT-COMP, I should find all offending modules.
     // For now, I will just simplify the numeral here.
-    parameter p0(mod(parameters[0].get_rational(), power_of_two(bv_size)));
+    parameter p0(mod(parameters[0].get_rational(), rational::power_of_two(bv_size)));
     parameter ps[2] = { p0, parameters[1] };
     sort * bv = get_bv_sort(bv_size);
     return m_manager->mk_const_decl(m_bv_sym, bv, func_decl_info(m_family_id, OP_BV_NUM, num_parameters, ps));
@@ -621,7 +601,7 @@ void bv_decl_plugin::get_offset_term(app * a, expr * & t, rational & offset) con
         offset = decl->get_parameter(0).get_rational();
         sz     = decl->get_parameter(1).get_int();
         t      = a->get_arg(1);
-        offset = mod(offset, power_of_two(sz));
+        offset = mod(offset, rational::power_of_two(sz));
     }
     else {
         t      = a;
@@ -729,37 +709,104 @@ expr * bv_decl_plugin::get_some_value(sort * s) {
     return m_manager->mk_app(m_family_id, OP_BV_NUM, 2, p, 0, 0);
 }
 
-bv_util::bv_util(ast_manager & m):
-    m_manager(m) {
-    SASSERT(m.has_plugin(symbol("bv")));
-    m_plugin = static_cast<bv_decl_plugin*>(m.get_plugin(m.get_family_id("bv")));
-}
-
-rational bv_util::norm(rational const & val, unsigned bv_size, bool is_signed) const {
-    rational r = mod(val, power_of_two(bv_size));
+rational bv_recognizers::norm(rational const & val, unsigned bv_size, bool is_signed) const {
+    rational r = mod(val, rational::power_of_two(bv_size));
     SASSERT(!r.is_neg());
     if (is_signed) {
-        if (r >= power_of_two(bv_size - 1)) {
-            r -= power_of_two(bv_size);
+        if (r >= rational::power_of_two(bv_size - 1)) {
+            r -= rational::power_of_two(bv_size);
         }
-        if (r < -power_of_two(bv_size - 1)) { 
-            r += power_of_two(bv_size);
+        if (r < -rational::power_of_two(bv_size - 1)) { 
+            r += rational::power_of_two(bv_size);
         }
     }
     return r;
 }
 
-bool bv_util::has_sign_bit(rational const & n, unsigned bv_size) const {
+bool bv_recognizers::has_sign_bit(rational const & n, unsigned bv_size) const {
     SASSERT(bv_size > 0);
     rational m = norm(n, bv_size, false);
-    rational p = power_of_two(bv_size - 1);
+    rational p = rational::power_of_two(bv_size - 1);
     return m >= p;
 }
 
-bool bv_util::is_bv_sort(sort const * s) const {
+bool bv_recognizers::is_bv_sort(sort const * s) const {
     return (s->get_family_id() == get_fid() && s->get_decl_kind() == BV_SORT && s->get_num_parameters() == 1); 
 }
 
+bool bv_recognizers::is_numeral(expr const * n, rational & val, unsigned & bv_size) const {
+    if (!is_app_of(n, get_fid(), OP_BV_NUM)) {
+        return false;
+    }
+    func_decl * decl = to_app(n)->get_decl();
+    val     = decl->get_parameter(0).get_rational();
+    bv_size = decl->get_parameter(1).get_int();
+    return true;
+}
+
+bool bv_recognizers::is_allone(expr const * e) const {
+    rational r;
+    unsigned bv_size;
+    if (!is_numeral(e, r, bv_size)) {
+        return false;
+    }
+    bool result = (r == rational::power_of_two(bv_size) - rational(1));
+    TRACE("is_allone", tout << r << " " << result << "\n";);
+    return result;
+}
+
+bool bv_recognizers::is_zero(expr const * n) const {
+    if (!is_app_of(n, get_fid(), OP_BV_NUM)) {
+        return false;
+    }
+    func_decl * decl = to_app(n)->get_decl();
+    return decl->get_parameter(0).get_rational().is_zero();
+}
+
+bool bv_recognizers::is_extract(expr const* e, unsigned& low, unsigned& high, expr*& b) {
+    if (!is_extract(e)) return false;
+    low = get_extract_low(e);
+    high = get_extract_high(e);
+    b = to_app(e)->get_arg(0);
+    return true;
+}
+
+bool bv_recognizers::is_bv2int(expr const* e, expr*& r) {
+    if (!is_bv2int(e)) return false;
+    r = to_app(e)->get_arg(0);
+    return true;
+}
+
+bool bv_recognizers::mult_inverse(rational const & n, unsigned bv_size, rational & result) {
+    if (n.is_one()) {
+        result = n;
+        return true;
+    }
+    
+    if (!mod(n, rational(2)).is_one()) {
+        return false;
+    }
+    
+    rational g;
+    rational x;
+    rational y;
+    g = gcd(n, rational::power_of_two(bv_size), x, y);
+    if (x.is_neg()) {
+        x = mod(x, rational::power_of_two(bv_size));
+    }
+    SASSERT(x.is_pos());
+    SASSERT(mod(x * n, rational::power_of_two(bv_size)).is_one());
+    result = x;
+    return true;
+}
+
+bv_util::bv_util(ast_manager & m):
+    bv_recognizers(m.mk_family_id(symbol("bv"))),
+    m_manager(m) {
+    SASSERT(m.has_plugin(symbol("bv")));
+    m_plugin = static_cast<bv_decl_plugin*>(m.get_plugin(m.mk_family_id("bv")));
+}
+
 app * bv_util::mk_numeral(rational const & val, sort* s) {
     if (!is_bv_sort(s)) {
         return 0;
@@ -774,67 +821,13 @@ app * bv_util::mk_numeral(rational const & val, unsigned bv_size) {
     return m_manager.mk_app(get_fid(), OP_BV_NUM, 2, p, 0, 0);
 }
 
-bool bv_util::is_numeral(expr const * n, rational & val, unsigned & bv_size) const {
-    if (!is_app_of(n, get_fid(), OP_BV_NUM)) {
-        return false;
-    }
-    func_decl * decl = to_app(n)->get_decl();
-    val     = decl->get_parameter(0).get_rational();
-    bv_size = decl->get_parameter(1).get_int();
-    return true;
-}
-
-
-bool bv_util::is_allone(expr const * e) const {
-    rational r;
-    unsigned bv_size;
-    if (!is_numeral(e, r, bv_size)) {
-        return false;
-    }
-    bool result = (r == power_of_two(bv_size) - rational(1));
-    TRACE("is_allone", tout << r << " " << result << "\n";);
-    return result;
-}
-
-bool bv_util::is_zero(expr const * n) const {
-    if (!is_app_of(n, get_fid(), OP_BV_NUM)) {
-        return false;
-    }
-    func_decl * decl = to_app(n)->get_decl();
-    return decl->get_parameter(0).get_rational().is_zero();
-}
-
 sort * bv_util::mk_sort(unsigned bv_size) {
     parameter p[1] = { parameter(bv_size) };
     return m_manager.mk_sort(get_fid(), BV_SORT, 1, p);
 }
 
-
-bool bv_util::mult_inverse(rational const & n, unsigned bv_size, rational & result) {
-    if (n.is_one()) {
-        result = n;
-        return true;
-    }
-    
-    if (!mod(n, rational(2)).is_one()) {
-        return false;
-    }
-    
-    rational g;
-    rational x;
-    rational y;
-    g = gcd(n, power_of_two(bv_size), x, y);
-    if (x.is_neg()) {
-        x = mod(x, power_of_two(bv_size));
-    }
-    SASSERT(x.is_pos());
-    SASSERT(mod(x * n, power_of_two(bv_size)).is_one());
-    result = x;
-    return true;
-}
-
 app * bv_util::mk_bv2int(expr* e) {
-    sort* s = m_manager.mk_sort(m_manager.get_family_id("arith"), INT_SORT);
+    sort* s = m_manager.mk_sort(m_manager.mk_family_id("arith"), INT_SORT);
     parameter p(s);
     return m_manager.mk_app(get_fid(), OP_BV2INT, 1, &p, 1, &e); 
 }
diff --git a/src/ast/bv_decl_plugin.h b/src/ast/bv_decl_plugin.h
index 34f2baf6b..8ea90f844 100644
--- a/src/ast/bv_decl_plugin.h
+++ b/src/ast/bv_decl_plugin.h
@@ -127,9 +127,6 @@ inline func_decl * get_div0_decl(ast_manager & m, func_decl * decl) {
 
 class bv_decl_plugin : public decl_plugin {
 protected:
-    vector<rational> m_powers;
-    void mk_table_upto(unsigned n);
-
     symbol m_bv_sym;
     symbol m_concat_sym;
     symbol m_sign_extend_sym;
@@ -245,8 +242,6 @@ protected:
 public:
     bv_decl_plugin();
 
-    rational power_of_two(unsigned n) const;
-
     virtual ~bv_decl_plugin() {}
     virtual void finalize();
 
@@ -273,7 +268,70 @@ public:
     virtual expr * get_some_value(sort * s);
 };
 
-class bv_util {
+class bv_recognizers {
+    family_id m_afid;
+public:
+    bv_recognizers(family_id fid):m_afid(fid) {}
+
+    family_id get_fid() const { return m_afid; }
+    family_id get_family_id() const { return get_fid(); }
+
+    bool is_numeral(expr const * n, rational & val, unsigned & bv_size) const;
+    bool is_numeral(expr const * n) const { return is_app_of(n, get_fid(), OP_BV_NUM); }
+    bool is_allone(expr const * e) const;
+    bool is_zero(expr const * e) const;
+    bool is_bv_sort(sort const * s) const;
+    bool is_bv(expr const* e) const {  return is_bv_sort(get_sort(e)); }
+    
+    bool is_concat(expr const * e) const { return is_app_of(e, get_fid(), OP_CONCAT); }
+    bool is_extract(func_decl const * f) const { return is_decl_of(f, get_fid(), OP_EXTRACT); }
+    bool is_extract(expr const * e) const { return is_app_of(e, get_fid(), OP_EXTRACT); }
+    unsigned get_extract_high(func_decl const * f) const { return f->get_parameter(0).get_int(); }
+    unsigned get_extract_low(func_decl const * f) const { return f->get_parameter(1).get_int(); }
+    unsigned get_extract_high(expr const * n) { SASSERT(is_extract(n)); return get_extract_high(to_app(n)->get_decl()); }
+    unsigned get_extract_low(expr const * n) { SASSERT(is_extract(n)); return get_extract_low(to_app(n)->get_decl()); }
+    bool is_extract(expr const * e, unsigned & low, unsigned & high, expr * & b);
+    bool is_bv2int(expr const * e, expr * & r);
+    bool is_bv_add(expr const * e) const { return is_app_of(e, get_fid(), OP_BADD); }
+    bool is_bv_sub(expr const * e) const { return is_app_of(e, get_fid(), OP_BSUB); }
+    bool is_bv_mul(expr const * e) const { return is_app_of(e, get_fid(), OP_BMUL); }
+    bool is_bv_neg(expr const * e) const { return is_app_of(e, get_fid(), OP_BNEG); }
+    bool is_bv_sdiv(expr const * e) const { return is_app_of(e, get_fid(), OP_BSDIV); }
+    bool is_bv_udiv(expr const * e) const { return is_app_of(e, get_fid(), OP_BUDIV); }
+    bool is_bv_srem(expr const * e) const { return is_app_of(e, get_fid(), OP_BSREM); }
+    bool is_bv_urem(expr const * e) const { return is_app_of(e, get_fid(), OP_BUREM); }
+    bool is_bv_smod(expr const * e) const { return is_app_of(e, get_fid(), OP_BSMOD); }
+    bool is_bv_and(expr const * e) const { return is_app_of(e, get_fid(), OP_BAND); }
+    bool is_bv_or(expr const * e) const { return is_app_of(e, get_fid(), OP_BOR); }
+    bool is_bv_xor(expr const * e) const { return is_app_of(e, get_fid(), OP_BXOR); }
+    bool is_bv_nand(expr const * e) const { return is_app_of(e, get_fid(), OP_BNAND); }
+    bool is_bv_nor(expr const * e) const { return is_app_of(e, get_fid(), OP_BNOR); }
+    bool is_bv_not(expr const * e) const { return is_app_of(e, get_fid(), OP_BNOT); }
+    bool is_bv_ule(expr const * e) const { return is_app_of(e, get_fid(), OP_ULEQ); }
+    bool is_bv_sle(expr const * e) const { return is_app_of(e, get_fid(), OP_SLEQ); }
+    bool is_bit2bool(expr const * e) const { return is_app_of(e, get_fid(), OP_BIT2BOOL); }
+    bool is_bv2int(expr const* e) const { return is_app_of(e, get_fid(), OP_BV2INT); }
+    bool is_int2bv(expr const* e) const { return is_app_of(e, get_fid(), OP_INT2BV); }
+    bool is_mkbv(expr const * e) const { return is_app_of(e, get_fid(), OP_MKBV); }
+    bool is_bv_ashr(expr const * e) const { return is_app_of(e, get_fid(), OP_BASHR); }
+    bool is_bv_lshr(expr const * e) const { return is_app_of(e, get_fid(), OP_BLSHR); }
+    bool is_bv_shl(expr const * e) const { return is_app_of(e, get_fid(), OP_BSHL); }
+    bool is_sign_ext(expr const * e) const { return is_app_of(e, get_fid(), OP_SIGN_EXT); }
+
+    MATCH_BINARY(is_bv_add);
+    MATCH_BINARY(is_bv_mul);
+    MATCH_BINARY(is_bv_sle);
+    MATCH_BINARY(is_bv_ule);
+    MATCH_BINARY(is_bv_shl);
+
+    rational norm(rational const & val, unsigned bv_size, bool is_signed) const ;
+    rational norm(rational const & val, unsigned bv_size) const { return norm(val, bv_size, false); }
+    bool has_sign_bit(rational const & n, unsigned bv_size) const;
+    bool mult_inverse(rational const & n, unsigned bv_size, rational & result);
+    
+};
+
+class bv_util : public bv_recognizers {
     ast_manager &    m_manager;
     bv_decl_plugin * m_plugin;
 
@@ -282,29 +340,10 @@ public:
 
     ast_manager & get_manager() const { return m_manager; }
 
-    family_id get_fid() const { return m_plugin->get_family_id(); }
-
-    family_id get_family_id() const { return get_fid(); }
-
-    rational power_of_two(unsigned n) const { return m_plugin->power_of_two(n); }
-
-    rational norm(rational const & val, unsigned bv_size, bool is_signed) const ;
-    rational norm(rational const & val, unsigned bv_size) const { return norm(val, bv_size, false); }
-    bool has_sign_bit(rational const & n, unsigned bv_size) const;
     app * mk_numeral(rational const & val, sort* s);
     app * mk_numeral(rational const & val, unsigned bv_size);
     app * mk_numeral(uint64 u, unsigned bv_size) { return mk_numeral(rational(u, rational::ui64()), bv_size); }
     sort * mk_sort(unsigned bv_size);
-    bool is_numeral(expr const * n, rational & val, unsigned & bv_size) const;
-    bool is_numeral(expr const * n) const {
-        return is_app_of(n, get_fid(), OP_BV_NUM);
-    }
-    bool is_allone(expr const * e) const;
-    bool is_zero(expr const * e) const;
-    bool is_bv_sort(sort const * s) const;
-    bool is_bv(expr const* e) const {
-        return is_bv_sort(m_manager.get_sort(e));
-    }
     
     unsigned get_bv_size(sort const * s) const { 
         SASSERT(is_bv_sort(s));
@@ -348,59 +387,6 @@ public:
     app * mk_bvumul_no_ovfl(expr* m, expr* n) { return m_manager.mk_app(get_fid(), OP_BUMUL_NO_OVFL, n, m); }
 
     app * mk_bv(unsigned n, expr* const* es) { return m_manager.mk_app(get_fid(), OP_MKBV, n, es); }
-
-    bool is_concat(expr const * e) const { return is_app_of(e, get_fid(), OP_CONCAT); }
-    bool is_extract(func_decl const * f) const { return is_decl_of(f, get_fid(), OP_EXTRACT); }
-    bool is_extract(expr const * e) const { return is_app_of(e, get_fid(), OP_EXTRACT); }
-    unsigned get_extract_high(func_decl const * f) const { return f->get_parameter(0).get_int(); }
-    unsigned get_extract_low(func_decl const * f) const { return f->get_parameter(1).get_int(); }
-    unsigned get_extract_high(expr const * n) { SASSERT(is_extract(n)); return get_extract_high(to_app(n)->get_decl()); }
-    unsigned get_extract_low(expr const * n) { SASSERT(is_extract(n)); return get_extract_low(to_app(n)->get_decl()); }
-    bool is_extract(expr const* e, unsigned& low, unsigned& high, expr*& b) {
-        if (!is_extract(e)) return false;
-        low = get_extract_low(e);
-        high = get_extract_high(e);
-        b = to_app(e)->get_arg(0);
-        return true;
-    }
-    bool is_bv2int(expr const* e, expr*& r) {
-        if (!is_bv2int(e)) return false;
-        r = to_app(e)->get_arg(0);
-        return true;
-    }
-    bool is_bv_add(expr const * e) const { return is_app_of(e, get_fid(), OP_BADD); }
-    bool is_bv_sub(expr const * e) const { return is_app_of(e, get_fid(), OP_BSUB); }
-    bool is_bv_mul(expr const * e) const { return is_app_of(e, get_fid(), OP_BMUL); }
-    bool is_bv_neg(expr const * e) const { return is_app_of(e, get_fid(), OP_BNEG); }
-    bool is_bv_sdiv(expr const * e) const { return is_app_of(e, get_fid(), OP_BSDIV); }
-    bool is_bv_udiv(expr const * e) const { return is_app_of(e, get_fid(), OP_BUDIV); }
-    bool is_bv_srem(expr const * e) const { return is_app_of(e, get_fid(), OP_BSREM); }
-    bool is_bv_urem(expr const * e) const { return is_app_of(e, get_fid(), OP_BUREM); }
-    bool is_bv_smod(expr const * e) const { return is_app_of(e, get_fid(), OP_BSMOD); }
-    bool is_bv_and(expr const * e) const { return is_app_of(e, get_fid(), OP_BAND); }
-    bool is_bv_or(expr const * e) const { return is_app_of(e, get_fid(), OP_BOR); }
-    bool is_bv_xor(expr const * e) const { return is_app_of(e, get_fid(), OP_BXOR); }
-    bool is_bv_nand(expr const * e) const { return is_app_of(e, get_fid(), OP_BNAND); }
-    bool is_bv_nor(expr const * e) const { return is_app_of(e, get_fid(), OP_BNOR); }
-    bool is_bv_not(expr const * e) const { return is_app_of(e, get_fid(), OP_BNOT); }
-    bool is_bv_ule(expr const * e) const { return is_app_of(e, get_fid(), OP_ULEQ); }
-    bool is_bv_sle(expr const * e) const { return is_app_of(e, get_fid(), OP_SLEQ); }
-    bool is_bit2bool(expr const * e) const { return is_app_of(e, get_fid(), OP_BIT2BOOL); }
-    bool is_bv2int(expr const* e) const { return is_app_of(e, get_fid(), OP_BV2INT); }
-    bool is_int2bv(expr const* e) const { return is_app_of(e, get_fid(), OP_INT2BV); }
-    bool is_mkbv(expr const * e) const { return is_app_of(e, get_fid(), OP_MKBV); }
-    bool is_bv_ashr(expr const * e) const { return is_app_of(e, get_fid(), OP_BASHR); }
-    bool is_bv_lshr(expr const * e) const { return is_app_of(e, get_fid(), OP_BLSHR); }
-    bool is_bv_shl(expr const * e) const { return is_app_of(e, get_fid(), OP_BSHL); }
-    bool is_sign_ext(expr const * e) const { return is_app_of(e, get_fid(), OP_SIGN_EXT); }
-
-    MATCH_BINARY(is_bv_add);
-    MATCH_BINARY(is_bv_mul);
-    MATCH_BINARY(is_bv_sle);
-    MATCH_BINARY(is_bv_ule);
-    MATCH_BINARY(is_bv_shl);
-
-    bool mult_inverse(rational const & n, unsigned bv_size, rational & result);
 };
     
 #endif /* _BV_DECL_PLUGIN_H_ */
diff --git a/src/ast/datatype_decl_plugin.cpp b/src/ast/datatype_decl_plugin.cpp
index 5cf841b49..0714af28b 100644
--- a/src/ast/datatype_decl_plugin.cpp
+++ b/src/ast/datatype_decl_plugin.cpp
@@ -673,7 +673,7 @@ bool datatype_decl_plugin::is_value(app * e) const {
 
 datatype_util::datatype_util(ast_manager & m):
     m_manager(m),
-    m_family_id(m.get_family_id("datatype")),
+    m_family_id(m.mk_family_id("datatype")),
     m_asts(m) {
 }
 
diff --git a/src/ast/decl_collector.cpp b/src/ast/decl_collector.cpp
index a83bf6b99..b663a9df3 100644
--- a/src/ast/decl_collector.cpp
+++ b/src/ast/decl_collector.cpp
@@ -45,7 +45,7 @@ decl_collector::decl_collector(ast_manager & m, bool preds):
     m_manager(m),
     m_sep_preds(preds) {
     m_basic_fid = m_manager.get_basic_family_id();
-    m_dt_fid    = m_manager.get_family_id("datatype");
+    m_dt_fid    = m_manager.mk_family_id("datatype");
 }
 
 void decl_collector::visit(ast* n) {
diff --git a/src/ast/dl_decl_plugin.cpp b/src/ast/dl_decl_plugin.cpp
index 5b73f944a..8ac19c11c 100644
--- a/src/ast/dl_decl_plugin.cpp
+++ b/src/ast/dl_decl_plugin.cpp
@@ -629,7 +629,7 @@ namespace datalog {
         m(m), 
         m_arith(m),
         m_bv(m),
-        m_fid(m.get_family_id(symbol("datalog_relation")))
+        m_fid(m.mk_family_id(symbol("datalog_relation")))
     {}
 
     // create a constant belonging to a given finite domain.
diff --git a/src/ast/float_decl_plugin.cpp b/src/ast/float_decl_plugin.cpp
index dbe7d5232..7f6d7f764 100644
--- a/src/ast/float_decl_plugin.cpp
+++ b/src/ast/float_decl_plugin.cpp
@@ -31,7 +31,7 @@ float_decl_plugin::float_decl_plugin():
 void float_decl_plugin::set_manager(ast_manager * m, family_id id) {
     decl_plugin::set_manager(m, id);
 
-    family_id aid = m_manager->get_family_id("arith");
+    family_id aid = m_manager->mk_family_id("arith");
     m_real_sort = m_manager->mk_sort(aid, REAL_SORT);
     SASSERT(m_real_sort != 0); // arith_decl_plugin must be installed before float_decl_plugin.
     m_manager->inc_ref(m_real_sort);
@@ -42,7 +42,7 @@ void float_decl_plugin::set_manager(ast_manager * m, family_id id) {
     
     if (m_manager->has_plugin(symbol("bv"))) {
         // bv plugin is optional, so m_bv_plugin may be 0
-        m_bv_fid = m_manager->get_family_id("bv");
+        m_bv_fid = m_manager->mk_family_id("bv");
         m_bv_plugin = static_cast<bv_decl_plugin*>(m_manager->get_plugin(m_bv_fid));
     }
 }
@@ -512,7 +512,7 @@ bool float_decl_plugin::is_value(app * e) const {
 
 float_util::float_util(ast_manager & m):
     m_manager(m),
-    m_fid(m.get_family_id("float")),
+    m_fid(m.mk_family_id("float")),
     m_a_util(m) {
     m_plugin = static_cast<float_decl_plugin*>(m.get_plugin(m_fid));
 }
diff --git a/src/ast/format.cpp b/src/ast/format.cpp
index 68ba5ea9a..1a36ca8ae 100644
--- a/src/ast/format.cpp
+++ b/src/ast/format.cpp
@@ -103,7 +103,7 @@ namespace format_ns {
         symbol f("format");
         if (!fm(m).has_plugin(f)) 
             fm(m).register_plugin(f, alloc(format_decl_plugin));
-        return fm(m).get_family_id(f);
+        return fm(m).mk_family_id(f);
     }
 
     static family_id fid(ast_manager & m) {
diff --git a/src/ast/macros/macro_util.cpp b/src/ast/macros/macro_util.cpp
index 4e457d270..cc710a82e 100644
--- a/src/ast/macros/macro_util.cpp
+++ b/src/ast/macros/macro_util.cpp
@@ -41,7 +41,7 @@ macro_util::macro_util(ast_manager & m, simplifier & s):
 
 arith_simplifier_plugin * macro_util::get_arith_simp() const {
     if (m_arith_simp == 0) {
-        const_cast<macro_util*>(this)->m_arith_simp = static_cast<arith_simplifier_plugin*>(m_simplifier.get_plugin(m_manager.get_family_id("arith")));
+        const_cast<macro_util*>(this)->m_arith_simp = static_cast<arith_simplifier_plugin*>(m_simplifier.get_plugin(m_manager.mk_family_id("arith")));
     }
     SASSERT(m_arith_simp != 0);
     return m_arith_simp;
@@ -49,7 +49,7 @@ arith_simplifier_plugin * macro_util::get_arith_simp() const {
 
 bv_simplifier_plugin * macro_util::get_bv_simp() const {
     if (m_bv_simp == 0) {
-        const_cast<macro_util*>(this)->m_bv_simp = static_cast<bv_simplifier_plugin*>(m_simplifier.get_plugin(m_manager.get_family_id("bv")));
+        const_cast<macro_util*>(this)->m_bv_simp = static_cast<bv_simplifier_plugin*>(m_simplifier.get_plugin(m_manager.mk_family_id("bv")));
     }
     SASSERT(m_bv_simp != 0);
     return m_bv_simp;
diff --git a/src/ast/normal_forms/defined_names.cpp b/src/ast/normal_forms/defined_names.cpp
index dab0ca0d8..16e9098fc 100644
--- a/src/ast/normal_forms/defined_names.cpp
+++ b/src/ast/normal_forms/defined_names.cpp
@@ -17,11 +17,67 @@ Revision History:
 
 --*/
 #include"defined_names.h"
+#include"obj_hashtable.h"
 #include"used_vars.h"
 #include"var_subst.h"
 #include"ast_smt2_pp.h"
 #include"ast_pp.h"
 
+struct defined_names::impl {
+    typedef obj_map<expr, app *>   expr2name;
+    typedef obj_map<expr, proof *> expr2proof;
+    ast_manager &    m_manager;
+    symbol           m_z3name;
+    
+    /**
+       \brief Mapping from expressions to their names. A name is an application.
+       If the expression does not have free variables, then the name is just a constant.
+    */
+    expr2name        m_expr2name;
+    /**
+       \brief Mapping from expressions to the apply-def proof.
+       That is, for each expression e, m_expr2proof[e] is the
+       proof e and m_expr2name[2] are observ. equivalent.
+       
+       This mapping is not used if proof production is disabled.
+    */
+    expr2proof       m_expr2proof;
+    
+    /**
+       \brief Domain of m_expr2name. It is used to keep the expressions
+       alive and for backtracking
+    */
+    expr_ref_vector  m_exprs; 
+    expr_ref_vector  m_names;        //!< Range of m_expr2name. It is used to keep the names alive.
+    proof_ref_vector m_apply_proofs; //!< Range of m_expr2proof. It is used to keep the def-intro proofs alive.
+    
+    
+    unsigned_vector m_lims;          //!< Backtracking support.
+    
+    impl(ast_manager & m, char const * prefix);
+    virtual ~impl();
+    
+    app * gen_name(expr * e, sort_ref_buffer & var_sorts, buffer<symbol> & var_names);
+    void cache_new_name(expr * e, app * name);
+    void cache_new_name_intro_proof(expr * e, proof * pr);
+    void bound_vars(sort_ref_buffer const & sorts, buffer<symbol> const & names, expr * def_conjunct, app * name, expr_ref & result);
+    void bound_vars(sort_ref_buffer const & sorts, buffer<symbol> const & names, expr * def_conjunct, app * name, expr_ref_buffer & result);
+    virtual void mk_definition(expr * e, app * n, sort_ref_buffer & var_sorts, buffer<symbol> const & var_names, expr_ref & new_def);
+    bool mk_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr);
+    void push_scope();
+    void pop_scope(unsigned num_scopes);
+    void reset();
+
+    unsigned get_num_names() const { return m_names.size(); }
+    func_decl * get_name_decl(unsigned i) const { return to_app(m_names.get(i))->get_decl(); }
+};
+
+struct defined_names::pos_impl : public defined_names::impl {
+    pos_impl(ast_manager & m, char const * fresh_prefix):impl(m, fresh_prefix) {}
+    virtual void mk_definition(expr * e, app * n, sort_ref_buffer & var_sorts, buffer<symbol> const & var_names, expr_ref & new_def);
+};
+
+
 defined_names::impl::impl(ast_manager & m, char const * prefix):
     m_manager(m),
     m_exprs(m),
@@ -222,5 +278,50 @@ void defined_names::impl::reset() {
     m_lims.reset();
 }
 
+defined_names::defined_names(ast_manager & m, char const * fresh_prefix) {
+    m_impl = alloc(impl, m, fresh_prefix);
+    m_pos_impl = alloc(pos_impl, m, fresh_prefix);
+}
+
+defined_names::~defined_names() {
+    dealloc(m_impl);
+    dealloc(m_pos_impl);
+}
+
+bool defined_names::mk_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr) {
+    return m_impl->mk_name(e, new_def, new_def_pr, n, pr);
+}
+
+bool defined_names::mk_pos_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr) {
+    return m_pos_impl->mk_name(e, new_def, new_def_pr, n, pr);
+}
+
+void defined_names::push() {
+    m_impl->push_scope();
+    m_pos_impl->push_scope();
+}
+
+void defined_names::pop(unsigned num_scopes) {
+    m_impl->pop_scope(num_scopes);
+    m_pos_impl->pop_scope(num_scopes);
+}
+
+void defined_names::reset() {
+    m_impl->reset();
+    m_pos_impl->reset();
+}
+
+unsigned defined_names::get_num_names() const { 
+    return m_impl->get_num_names() + m_pos_impl->get_num_names();
+}
+
+func_decl * defined_names::get_name_decl(unsigned i) const { 
+    SASSERT(i < get_num_names());
+    unsigned n1 = m_impl->get_num_names();
+    return i < n1 ? m_impl->get_name_decl(i) : m_pos_impl->get_name_decl(i - n1);
+}
+
+
+
 
 
diff --git a/src/ast/normal_forms/defined_names.h b/src/ast/normal_forms/defined_names.h
index c5e4a116f..0b9f04569 100644
--- a/src/ast/normal_forms/defined_names.h
+++ b/src/ast/normal_forms/defined_names.h
@@ -21,7 +21,6 @@ Revision History:
 #define _DEFINED_NAMES_H_
 
 #include"ast.h"
-#include"obj_hashtable.h"
 
 /**
    \brief Mapping from expressions to skolem functions that are used to name them.
@@ -29,62 +28,13 @@ Revision History:
    The mapping supports backtracking using the methods #push_scope and #pop_scope.
 */
 class defined_names {
-
-    struct impl {
-        typedef obj_map<expr, app *>   expr2name;
-        typedef obj_map<expr, proof *> expr2proof;
-        ast_manager &    m_manager;
-        symbol           m_z3name;
-        
-        /**
-           \brief Mapping from expressions to their names. A name is an application.
-           If the expression does not have free variables, then the name is just a constant.
-        */
-        expr2name        m_expr2name;
-        /**
-           \brief Mapping from expressions to the apply-def proof.
-           That is, for each expression e, m_expr2proof[e] is the
-           proof e and m_expr2name[2] are observ. equivalent.
-           
-           This mapping is not used if proof production is disabled.
-        */
-        expr2proof       m_expr2proof;
-        
-        /**
-           \brief Domain of m_expr2name. It is used to keep the expressions
-           alive and for backtracking
-        */
-        expr_ref_vector  m_exprs; 
-        expr_ref_vector  m_names;        //!< Range of m_expr2name. It is used to keep the names alive.
-        proof_ref_vector m_apply_proofs; //!< Range of m_expr2proof. It is used to keep the def-intro proofs alive.
-        
-        
-        unsigned_vector m_lims;          //!< Backtracking support.
-
-        impl(ast_manager & m, char const * prefix);
-        virtual ~impl();
-
-        app * gen_name(expr * e, sort_ref_buffer & var_sorts, buffer<symbol> & var_names);
-        void cache_new_name(expr * e, app * name);
-        void cache_new_name_intro_proof(expr * e, proof * pr);
-        void bound_vars(sort_ref_buffer const & sorts, buffer<symbol> const & names, expr * def_conjunct, app * name, expr_ref & result);
-        void bound_vars(sort_ref_buffer const & sorts, buffer<symbol> const & names, expr * def_conjunct, app * name, expr_ref_buffer & result);
-        virtual void mk_definition(expr * e, app * n, sort_ref_buffer & var_sorts, buffer<symbol> const & var_names, expr_ref & new_def);
-        bool mk_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr);
-        void push_scope();
-        void pop_scope(unsigned num_scopes);
-        void reset();
-    };
-
-    struct pos_impl : public impl {
-        pos_impl(ast_manager & m, char const * fresh_prefix):impl(m, fresh_prefix) {}
-        virtual void mk_definition(expr * e, app * n, sort_ref_buffer & var_sorts, buffer<symbol> const & var_names, expr_ref & new_def);
-    };
-    
-    impl      m_impl;
-    pos_impl  m_pos_impl;
+    struct impl;
+    struct pos_impl;
+    impl      * m_impl;
+    pos_impl  * m_pos_impl;
 public:
-    defined_names(ast_manager & m, char const * fresh_prefix = "z3name"):m_impl(m, fresh_prefix), m_pos_impl(m, fresh_prefix) {}
+    defined_names(ast_manager & m, char const * fresh_prefix = "z3name");
+    ~defined_names();
 
     // -----------------------------------
     //
@@ -113,9 +63,7 @@ public:
 
        Remark: the definitions are closed with an universal quantifier if e contains free variables.
     */
-    bool mk_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr) {
-        return m_impl.mk_name(e, new_def, new_def_pr, n, pr);
-    }
+    bool mk_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr);
 
     /**
        \brief Create a name for a positive occurrence of the expression \c e.
@@ -127,24 +75,14 @@ public:
 
        Remark: the definitions are closed with an universal quantifier if e contains free variables.
     */
-    bool mk_pos_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr) {
-        return m_pos_impl.mk_name(e, new_def, new_def_pr, n, pr);
-    }
+    bool mk_pos_name(expr * e, expr_ref & new_def, proof_ref & new_def_pr, app_ref & n, proof_ref & pr);
 
-    void push_scope() {
-        m_impl.push_scope();
-        m_pos_impl.push_scope();
-    }
+    void push();
+    void pop(unsigned num_scopes);
+    void reset();
 
-    void pop_scope(unsigned num_scopes) {
-        m_impl.pop_scope(num_scopes);
-        m_pos_impl.pop_scope(num_scopes);
-    }
-
-    void reset() {
-        m_impl.reset();
-        m_pos_impl.reset();
-    }
+    unsigned get_num_names() const;
+    func_decl * get_name_decl(unsigned i) const;
 };
 
 #endif /* _DEFINED_NAMES_H_ */
diff --git a/src/ast/pattern/pattern_inference.cpp b/src/ast/pattern/pattern_inference.cpp
index 773b9a2f5..83362f5b3 100644
--- a/src/ast/pattern/pattern_inference.cpp
+++ b/src/ast/pattern/pattern_inference.cpp
@@ -91,7 +91,7 @@ pattern_inference::pattern_inference(ast_manager & m, pattern_inference_params &
     simplifier(m),
     m_params(params),
     m_bfid(m.get_basic_family_id()),
-    m_afid(m.get_family_id("arith")),
+    m_afid(m.mk_family_id("arith")),
     m_le(m),
     m_nested_arith_only(true),
     m_block_loop_patterns(params.m_pi_block_loop_patterns),
diff --git a/src/ast/pattern/pattern_inference.h b/src/ast/pattern/pattern_inference.h
index 1a179e794..97897835c 100644
--- a/src/ast/pattern/pattern_inference.h
+++ b/src/ast/pattern/pattern_inference.h
@@ -150,7 +150,7 @@ class pattern_inference : public simplifier {
         void save_candidate(expr * n, unsigned delta);
         void reset();
     public:
-        collect(ast_manager & m, pattern_inference & o):m_manager(m), m_owner(o), m_afid(m.get_family_id("arith")) {}
+        collect(ast_manager & m, pattern_inference & o):m_manager(m), m_owner(o), m_afid(m.mk_family_id("arith")) {}
         void operator()(expr * n, unsigned num_bindings);
     };
 
diff --git a/src/ast/proof_checker/proof_checker.cpp b/src/ast/proof_checker/proof_checker.cpp
index 240504048..85e0cc791 100644
--- a/src/ast/proof_checker/proof_checker.cpp
+++ b/src/ast/proof_checker/proof_checker.cpp
@@ -85,7 +85,7 @@ proof_checker::proof_checker(ast_manager& m) : m(m), m_todo(m), m_marked(), m_pi
     if (!m.has_plugin(fam_name)) {
         m.register_plugin(fam_name, alloc(hyp_decl_plugin));
     }
-    m_hyp_fid = m.get_family_id(fam_name);
+    m_hyp_fid = m.mk_family_id(fam_name);
     // m_spc_fid = m.get_family_id("spc");
     m_nil = m.mk_const(m_hyp_fid, OP_NIL);
 }
diff --git a/src/ast/reg_decl_plugins.cpp b/src/ast/reg_decl_plugins.cpp
index fd4d49789..ab1844e07 100644
--- a/src/ast/reg_decl_plugins.cpp
+++ b/src/ast/reg_decl_plugins.cpp
@@ -27,25 +27,25 @@ Revision History:
 #include"float_decl_plugin.h"
 
 void reg_decl_plugins(ast_manager & m) {
-    if (!m.get_plugin(m.get_family_id(symbol("arith")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("arith")))) {
         m.register_plugin(symbol("arith"), alloc(arith_decl_plugin));
     }
-    if (!m.get_plugin(m.get_family_id(symbol("bv")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("bv")))) {
         m.register_plugin(symbol("bv"), alloc(bv_decl_plugin));
     }
-    if (!m.get_plugin(m.get_family_id(symbol("array")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("array")))) {
         m.register_plugin(symbol("array"), alloc(array_decl_plugin));
     }
-    if (!m.get_plugin(m.get_family_id(symbol("datatype")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("datatype")))) {
         m.register_plugin(symbol("datatype"), alloc(datatype_decl_plugin));    
     }
-    if (!m.get_plugin(m.get_family_id(symbol("datalog_relation")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("datalog_relation")))) {
         m.register_plugin(symbol("datalog_relation"), alloc(datalog::dl_decl_plugin));
     }
-    if (!m.get_plugin(m.get_family_id(symbol("seq")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("seq")))) {
         m.register_plugin(symbol("seq"), alloc(seq_decl_plugin));
     }
-    if (!m.get_plugin(m.get_family_id(symbol("float")))) {
+    if (!m.get_plugin(m.mk_family_id(symbol("float")))) {
         m.register_plugin(symbol("float"), alloc(float_decl_plugin));
     }
 }
diff --git a/src/ast/rewriter/bit_blaster/bit_blaster.h b/src/ast/rewriter/bit_blaster/bit_blaster.h
index 42444aebc..7b317c6cb 100644
--- a/src/ast/rewriter/bit_blaster/bit_blaster.h
+++ b/src/ast/rewriter/bit_blaster/bit_blaster.h
@@ -36,7 +36,7 @@ public:
     bit_blaster_cfg(bv_util & u, bit_blaster_params const & p, basic_simplifier_plugin & _s);
 
     ast_manager & m() const { return m_util.get_manager(); }
-    numeral power(unsigned n) const { return m_util.power_of_two(n); }
+    numeral power(unsigned n) const { return rational::power_of_two(n); }
     void mk_xor(expr * a, expr * b, expr_ref & r) { s.mk_xor(a, b, r); }
     void mk_xor3(expr * a, expr * b, expr * c, expr_ref & r);
     void mk_carry(expr * a, expr * b, expr * c, expr_ref & r);
diff --git a/src/ast/rewriter/bit_blaster/bit_blaster_rewriter.cpp b/src/ast/rewriter/bit_blaster/bit_blaster_rewriter.cpp
index 1fd83e91f..80d319377 100644
--- a/src/ast/rewriter/bit_blaster/bit_blaster_rewriter.cpp
+++ b/src/ast/rewriter/bit_blaster/bit_blaster_rewriter.cpp
@@ -32,7 +32,7 @@ struct blaster_cfg {
     blaster_cfg(bool_rewriter & r, bv_util & u):m_rewriter(r), m_util(u) {}
     
     ast_manager & m() const { return m_util.get_manager(); }
-    numeral power(unsigned n) const { return m_util.power_of_two(n); }
+    numeral power(unsigned n) const { return rational::power_of_two(n); }
     void mk_xor(expr * a, expr * b, expr_ref & r) { m_rewriter.mk_xor(a, b, r); }
     void mk_xor3(expr * a, expr * b, expr * c, expr_ref & r) {
         expr_ref tmp(m());
diff --git a/src/ast/rewriter/bool_rewriter.cpp b/src/ast/rewriter/bool_rewriter.cpp
index b5f18a461..5b0c38616 100644
--- a/src/ast/rewriter/bool_rewriter.cpp
+++ b/src/ast/rewriter/bool_rewriter.cpp
@@ -27,6 +27,7 @@ void bool_rewriter::updt_params(params_ref const & _p) {
     m_local_ctx            = p.local_ctx();
     m_local_ctx_limit      = p.local_ctx_limit();
     m_blast_distinct       = p.blast_distinct();
+    m_blast_distinct_threshold = p.blast_distinct_threshold();
     m_ite_extra_rules      = p.ite_extra_rules();
 }
 
@@ -746,7 +747,7 @@ br_status bool_rewriter::mk_distinct_core(unsigned num_args, expr * const * args
         return BR_DONE;
     }
 
-    if (m_blast_distinct) {
+    if (m_blast_distinct && num_args < m_blast_distinct_threshold) {
         ptr_buffer<expr> new_diseqs;
         for (unsigned i = 0; i < num_args; i++) {
             for (unsigned j = i + 1; j < num_args; j++)
diff --git a/src/ast/rewriter/bool_rewriter.h b/src/ast/rewriter/bool_rewriter.h
index b1a177247..ef6dc2d38 100644
--- a/src/ast/rewriter/bool_rewriter.h
+++ b/src/ast/rewriter/bool_rewriter.h
@@ -55,6 +55,7 @@ class bool_rewriter {
     bool           m_local_ctx;
     bool           m_elim_and;
     bool           m_blast_distinct;
+    unsigned       m_blast_distinct_threshold;
     bool           m_ite_extra_rules;
     unsigned       m_local_ctx_limit;
     unsigned       m_local_ctx_cost;
diff --git a/src/ast/rewriter/bool_rewriter_params.pyg b/src/ast/rewriter/bool_rewriter_params.pyg
index a5bcf6f5d..531bf4db9 100644
--- a/src/ast/rewriter/bool_rewriter_params.pyg
+++ b/src/ast/rewriter/bool_rewriter_params.pyg
@@ -6,4 +6,6 @@ def_module_params(module_name='rewriter',
                           ("elim_and", BOOL, False, "conjunctions are rewritten using negation and disjunctions"),
                           ("local_ctx", BOOL, False, "perform local (i.e., cheap) context simplifications"),
                           ("local_ctx_limit", UINT, UINT_MAX, "limit for applying local context simplifier"),
-                          ("blast_distinct", BOOL, False, "expand a distinct predicate into a quadratic number of disequalities")))
+                          ("blast_distinct", BOOL, False, "expand a distinct predicate into a quadratic number of disequalities"), 
+                          ("blast_distinct_threshold", UINT, UINT_MAX, "when blast_distinct is true, only distinct expressions with less than this number of arguments are blasted")  
+                          ))
diff --git a/src/ast/rewriter/bv_rewriter.cpp b/src/ast/rewriter/bv_rewriter.cpp
index 5fd562676..f8ff27337 100644
--- a/src/ast/rewriter/bv_rewriter.cpp
+++ b/src/ast/rewriter/bv_rewriter.cpp
@@ -283,12 +283,12 @@ br_status bv_rewriter::mk_leq_core(bool is_signed, expr * a, expr * b, expr_ref
 
     if (is_num1 || is_num2) {
         if (is_signed) {
-            lower = - m_util.power_of_two(sz - 1);
-            upper =   m_util.power_of_two(sz - 1) - numeral(1);
+            lower = - rational::power_of_two(sz - 1);
+            upper =   rational::power_of_two(sz - 1) - numeral(1);
         }
         else {
             lower = numeral(0);
-            upper = m_util.power_of_two(sz) - numeral(1);
+            upper = rational::power_of_two(sz) - numeral(1);
         }
     }
 
@@ -387,14 +387,14 @@ br_status bv_rewriter::mk_extract(unsigned high, unsigned low, expr * arg, expr_
     if (is_numeral(arg, v, sz)) {
         sz = high - low + 1;
         if (v.is_neg())
-            mod(v, m_util.power_of_two(sz), v);
+            mod(v, rational::power_of_two(sz), v);
         if (v.is_uint64()) {
             uint64 u  = v.get_uint64();
             uint64 e  = shift_right(u, low) & (shift_left(1ull, sz) - 1ull);
             result    = mk_numeral(numeral(e, numeral::ui64()), sz);
             return BR_DONE;
         }
-        div(v, m_util.power_of_two(low), v);
+        div(v, rational::power_of_two(low), v);
         result = mk_numeral(v, sz);
         return BR_DONE;
     }
@@ -519,7 +519,7 @@ br_status bv_rewriter::mk_bv_shl(expr * arg1, expr * arg2, expr_ref & result) {
             
             SASSERT(r2 < numeral(bv_size));
             SASSERT(r2.is_unsigned());
-            r1 = m_util.norm(r1 * m_util.power_of_two(r2.get_unsigned()), bv_size);
+            r1 = m_util.norm(r1 * rational::power_of_two(r2.get_unsigned()), bv_size);
             result = mk_numeral(r1, bv_size);
             return BR_DONE;
         }
@@ -567,7 +567,7 @@ br_status bv_rewriter::mk_bv_lshr(expr * arg1, expr * arg2, expr_ref & result) {
 
             SASSERT(r2.is_unsigned());
             unsigned sh = r2.get_unsigned();
-            div(r1, m_util.power_of_two(sh), r1);
+            div(r1, rational::power_of_two(sh), r1);
             result = mk_numeral(r1, bv_size);
             return BR_DONE;
         }
@@ -626,7 +626,7 @@ br_status bv_rewriter::mk_bv_ashr(expr * arg1, expr * arg2, expr_ref & result) {
 
     if (is_num1 && is_num2 && numeral(bv_size) <= r2) {
         if (m_util.has_sign_bit(r1, bv_size))
-            result = mk_numeral(m_util.power_of_two(bv_size) - numeral(1), bv_size);
+            result = mk_numeral(rational::power_of_two(bv_size) - numeral(1), bv_size);
         else
             result = mk_numeral(0, bv_size);
         return BR_DONE;
@@ -635,7 +635,7 @@ br_status bv_rewriter::mk_bv_ashr(expr * arg1, expr * arg2, expr_ref & result) {
     if (is_num1 && is_num2) {
         SASSERT(r2 < numeral(bv_size));
         bool   sign = m_util.has_sign_bit(r1, bv_size);
-        div(r1, m_util.power_of_two(r2.get_unsigned()), r1);
+        div(r1, rational::power_of_two(r2.get_unsigned()), r1);
         if (sign) {
             // pad ones.
             numeral p(1);
@@ -697,7 +697,7 @@ br_status bv_rewriter::mk_bv_sdiv_core(expr * arg1, expr * arg2, bool hi_div0, e
                 // The "hardware interpretation" for (bvsdiv x 0) is (ite (bvslt x #x0000) #x0001 #xffff)
                 result = m().mk_ite(m().mk_app(get_fid(), OP_SLT, arg1, mk_numeral(0, bv_size)),
                                     mk_numeral(1, bv_size),
-                                    mk_numeral(m_util.power_of_two(bv_size) - numeral(1), bv_size));
+                                    mk_numeral(rational::power_of_two(bv_size) - numeral(1), bv_size));
                 return BR_REWRITE2;
             }
         }
@@ -746,7 +746,7 @@ br_status bv_rewriter::mk_bv_udiv_core(expr * arg1, expr * arg2, bool hi_div0, e
             }
             else {
                 // The "hardware interpretation" for (bvudiv x 0) is #xffff
-                result = mk_numeral(m_util.power_of_two(bv_size) - numeral(1), bv_size);
+                result = mk_numeral(rational::power_of_two(bv_size) - numeral(1), bv_size);
                 return BR_DONE;
                 
             }
@@ -845,7 +845,7 @@ bool bv_rewriter::is_minus_one_core(expr * arg) const {
     numeral r;
     unsigned bv_size;
     if (is_numeral(arg, r, bv_size)) {
-        return r == (m_util.power_of_two(bv_size) - numeral(1));
+        return r == (rational::power_of_two(bv_size) - numeral(1));
     }
     return false;
 }
@@ -924,7 +924,7 @@ br_status bv_rewriter::mk_bv_urem_core(expr * arg1, expr * arg2, bool hi_div0, e
         if (is_x_minus_one(arg1, x) && x == arg2) {
             bv_size = get_bv_size(arg1);
             expr * x_minus_1 = arg1;
-            expr * minus_one = mk_numeral(m_util.power_of_two(bv_size) - numeral(1), bv_size);
+            expr * minus_one = mk_numeral(rational::power_of_two(bv_size) - numeral(1), bv_size);
             result = m().mk_ite(m().mk_eq(x, mk_numeral(0, bv_size)),
                                 m().mk_app(get_fid(), OP_BUREM0, minus_one),
                                 x_minus_1);
@@ -1068,7 +1068,7 @@ br_status bv_rewriter::mk_concat(unsigned num_args, expr * const * args, expr_re
         if (i > 0) 
             prev = new_args.back();
         if (is_numeral(arg, v1, sz1) && prev != 0 && is_numeral(prev, v2, sz2)) {
-            v2  *= m_util.power_of_two(sz1);
+            v2  *= rational::power_of_two(sz1);
             v2  += v1;
             new_args.pop_back();
             new_args.push_back(mk_numeral(v2, sz1+sz2));
@@ -1137,7 +1137,7 @@ br_status bv_rewriter::mk_sign_extend(unsigned n, expr * arg, expr_ref & result)
     if (is_numeral(arg, r, bv_size)) {
         unsigned result_bv_size = bv_size + n;
         r = m_util.norm(r, bv_size, true);
-        mod(r, m_util.power_of_two(result_bv_size), r);
+        mod(r, rational::power_of_two(result_bv_size), r);
         result = mk_numeral(r, result_bv_size);
         return BR_DONE;
     }
@@ -1213,7 +1213,7 @@ br_status bv_rewriter::mk_bv_or(unsigned num, expr * const * args, expr_ref & re
         if (m_util.is_bv_not(arg)) {
             expr * atom = to_app(arg)->get_arg(0);
             if (pos_args.is_marked(atom)) {
-                result = mk_numeral(m_util.power_of_two(sz) - numeral(1), sz);
+                result = mk_numeral(rational::power_of_two(sz) - numeral(1), sz);
                 return BR_DONE;
             }
             else if (neg_args.is_marked(atom)) {
@@ -1229,7 +1229,7 @@ br_status bv_rewriter::mk_bv_or(unsigned num, expr * const * args, expr_ref & re
                 continue;
             }
             else if (neg_args.is_marked(arg)) {
-                result = mk_numeral(m_util.power_of_two(sz) - numeral(1), sz);
+                result = mk_numeral(rational::power_of_two(sz) - numeral(1), sz);
                 return BR_DONE;
             }
             pos_args.mark(arg, true);
@@ -1237,7 +1237,7 @@ br_status bv_rewriter::mk_bv_or(unsigned num, expr * const * args, expr_ref & re
         }
     }
 
-    if (v1 == m_util.power_of_two(sz) - numeral(1)) {
+    if (v1 == rational::power_of_two(sz) - numeral(1)) {
         result = mk_numeral(v1, sz);
         return BR_DONE;
     }
@@ -1294,7 +1294,7 @@ br_status bv_rewriter::mk_bv_or(unsigned num, expr * const * args, expr_ref & re
             }
             if (i != low) {
                 unsigned num_sz = i - low;
-                exs.push_back(m_util.mk_numeral(m_util.power_of_two(num_sz) - numeral(1), num_sz));
+                exs.push_back(m_util.mk_numeral(rational::power_of_two(num_sz) - numeral(1), num_sz));
                 low = i;
             }
             while (i < sz && mod(v1, two).is_zero()) {
@@ -1385,7 +1385,7 @@ br_status bv_rewriter::mk_bv_xor(unsigned num, expr * const * args, expr_ref & r
             else if (pos_args.is_marked(atom)) {
                 pos_args.mark(atom, false);
                 merged = true;
-                v1 = bitwise_xor(v1, m_util.power_of_two(sz) - numeral(1));
+                v1 = bitwise_xor(v1, rational::power_of_two(sz) - numeral(1));
             }
             else {
                 neg_args.mark(atom, true);
@@ -1399,7 +1399,7 @@ br_status bv_rewriter::mk_bv_xor(unsigned num, expr * const * args, expr_ref & r
             else if (neg_args.is_marked(arg)) {
                 neg_args.mark(arg, false);
                 merged = true;
-                v1 = bitwise_xor(v1, m_util.power_of_two(sz) - numeral(1));
+                v1 = bitwise_xor(v1, rational::power_of_two(sz) - numeral(1));
             }
             else {
                 pos_args.mark(arg, true);
@@ -1455,7 +1455,7 @@ br_status bv_rewriter::mk_bv_xor(unsigned num, expr * const * args, expr_ref & r
         return BR_REWRITE3;
     } 
 
-    if (!merged && !flattened && (num_coeffs == 0 || (num_coeffs == 1 && !v1.is_zero() && v1 != (m_util.power_of_two(sz) - numeral(1)))))
+    if (!merged && !flattened && (num_coeffs == 0 || (num_coeffs == 1 && !v1.is_zero() && v1 != (rational::power_of_two(sz) - numeral(1)))))
         return BR_FAILED;
 
     ptr_buffer<expr> new_args;
@@ -1611,7 +1611,7 @@ br_status bv_rewriter::mk_bv_redand(expr * arg, expr_ref & result) {
     numeral r;
     unsigned bv_size;
     if (is_numeral(arg, r, bv_size)) {
-        result = (r == m_util.power_of_two(bv_size) - numeral(1)) ? mk_numeral(1, 1) : mk_numeral(0, 1);
+        result = (r == rational::power_of_two(bv_size) - numeral(1)) ? mk_numeral(1, 1) : mk_numeral(0, 1);
         return BR_DONE;
     }
     return BR_FAILED;
@@ -1707,7 +1707,7 @@ bool bv_rewriter::is_zero_bit(expr * x, unsigned idx) {
     if (is_numeral(x, val, bv_size)) {
         if (val.is_zero())
             return true;
-        div(val, m_util.power_of_two(idx), val);
+        div(val, rational::power_of_two(idx), val);
         return (val % numeral(2)).is_zero();
     }
     if (m_util.is_concat(x)) {
diff --git a/src/ast/rewriter/float_rewriter.cpp b/src/ast/rewriter/float_rewriter.cpp
index 9678af216..482e280e3 100644
--- a/src/ast/rewriter/float_rewriter.cpp
+++ b/src/ast/rewriter/float_rewriter.cpp
@@ -443,4 +443,4 @@ br_status float_rewriter::mk_eq_core(expr * arg1, expr * arg2, expr_ref & result
 
 br_status float_rewriter::mk_to_ieee_bv(expr * arg1, expr_ref & result) {
     return BR_FAILED;
-}
\ No newline at end of file
+}
diff --git a/src/ast/simplifier/bv_elim.cpp b/src/ast/simplifier/bv_elim.cpp
index 3238d13e7..5c19a245e 100644
--- a/src/ast/simplifier/bv_elim.cpp
+++ b/src/ast/simplifier/bv_elim.cpp
@@ -15,7 +15,7 @@ void bv_elim::elim(quantifier* q, quantifier_ref& r) {
     expr_ref         new_body(m_manager);
     expr*            old_body = q->get_expr();
     unsigned num_decls = q->get_num_decls();
-    family_id bfid = m_manager.get_family_id("bv");
+    family_id bfid = m_manager.mk_family_id("bv");
 
     //
     // Traverse sequence of bound variables to eliminate
diff --git a/src/ast/simplifier/bv_simplifier_plugin.cpp b/src/ast/simplifier/bv_simplifier_plugin.cpp
index 2da1f3bab..3ef55baba 100644
--- a/src/ast/simplifier/bv_simplifier_plugin.cpp
+++ b/src/ast/simplifier/bv_simplifier_plugin.cpp
@@ -76,9 +76,9 @@ app * bv_simplifier_plugin::mk_numeral(numeral const & n) {
 }
 
 app * bv_simplifier_plugin::mk_numeral(numeral const& n, unsigned bv_size) {
-    numeral r = mod(n, m_util.power_of_two(bv_size));
+    numeral r = mod(n, rational::power_of_two(bv_size));
     SASSERT(!r.is_neg());
-    SASSERT(r < m_util.power_of_two(bv_size));
+    SASSERT(r < rational::power_of_two(bv_size));
     return m_util.mk_numeral(r, bv_size);
 }
 
@@ -225,7 +225,7 @@ inline uint64 bv_simplifier_plugin::to_uint64(const numeral & n, unsigned bv_siz
     SASSERT(bv_size <= 64);
     numeral tmp = n;
     if (tmp.is_neg()) {
-        tmp = mod(tmp, m_util.power_of_two(bv_size));
+        tmp = mod(tmp, rational::power_of_two(bv_size));
     }
     SASSERT(tmp.is_nonneg());
     SASSERT(tmp.is_uint64());
@@ -235,7 +235,7 @@ inline uint64 bv_simplifier_plugin::to_uint64(const numeral & n, unsigned bv_siz
 #define MK_BV_OP(_oper_,_binop_) \
 rational bv_simplifier_plugin::mk_bv_ ## _oper_(numeral const& a0, numeral const& b0, unsigned sz) { \
     rational r(0), a(a0), b(b0); \
-    numeral p64 = m_util.power_of_two(64); \
+    numeral p64 = rational::power_of_two(64); \
     numeral mul(1); \
     while (sz > 0) { \
         numeral a1 = a % p64; \
@@ -260,7 +260,7 @@ MK_BV_OP(xor,^)
 
 rational bv_simplifier_plugin::mk_bv_not(numeral const& a0, unsigned sz) { 
     rational r(0), a(a0), mul(1);
-    numeral p64 = m_util.power_of_two(64); 
+    numeral p64 = rational::power_of_two(64); 
     while (sz > 0) { 
         numeral a1 = a % p64; 
         uint64 u = ~a1.get_uint64();
@@ -320,12 +320,12 @@ void bv_simplifier_plugin::mk_leq_core(bool is_signed, expr * arg1, expr * arg2,
 
     if (is_num1 || is_num2) {
         if (is_signed) {
-            lower = - m_util.power_of_two(bv_size - 1);
-            upper =   m_util.power_of_two(bv_size - 1) - numeral(1);
+            lower = - rational::power_of_two(bv_size - 1);
+            upper =   rational::power_of_two(bv_size - 1) - numeral(1);
         }
         else {
             lower = numeral(0);
-            upper = m_util.power_of_two(bv_size) - numeral(1);
+            upper = rational::power_of_two(bv_size) - numeral(1);
         }
     }
 
@@ -509,7 +509,7 @@ bool bv_simplifier_plugin::try_mk_extract(unsigned high, unsigned low, expr * ar
 
     if (m_util.is_numeral(a, r, num_bits)) {
         if (r.is_neg()) {
-            r = mod(r, m_util.power_of_two(sz));
+            r = mod(r, rational::power_of_two(sz));
         }
         SASSERT(r.is_nonneg());
         if (r.is_uint64()) {
@@ -520,7 +520,7 @@ bool bv_simplifier_plugin::try_mk_extract(unsigned high, unsigned low, expr * ar
             result = mk_numeral(numeral(e, numeral::ui64()), sz);
             return true;
         }
-        result = mk_numeral(div(r, m_util.power_of_two(low)), sz);
+        result = mk_numeral(div(r, rational::power_of_two(low)), sz);
         return true;
     }
     // (extract[high:low] (extract[high2:low2] x)) == (extract[high+low2 : low+low2] x)
@@ -902,7 +902,7 @@ void bv_simplifier_plugin::mk_concat(unsigned num_args, expr * const * args, exp
         --i;
         expr * arg   = args[i];
         if (is_numeral(arg, arg_val)) {
-            arg_val    *= m_util.power_of_two(shift);
+            arg_val    *= rational::power_of_two(shift);
             val        += arg_val;
             shift      += get_bv_size(arg);
             TRACE("bv_simplifier_plugin", 
@@ -1203,7 +1203,7 @@ bool bv_simplifier_plugin::is_minus_one_core(expr * arg) const {
     unsigned bv_size;
     if (m_util.is_numeral(arg, r, bv_size)) {
         numeral minus_one(-1);
-        minus_one = mod(minus_one, m_util.power_of_two(bv_size));
+        minus_one = mod(minus_one, rational::power_of_two(bv_size));
         return r == minus_one;
     }
     return false;
@@ -1295,7 +1295,7 @@ void bv_simplifier_plugin::mk_sign_extend(unsigned n, expr * arg, expr_ref & res
     if (m_util.is_numeral(arg, r, bv_size)) {
         unsigned result_bv_size = bv_size + n;
         r = norm(r, bv_size, true);
-        r = mod(r, m_util.power_of_two(result_bv_size));
+        r = mod(r, rational::power_of_two(result_bv_size));
         result = mk_numeral(r, result_bv_size);
         TRACE("mk_sign_extend", tout << "n: " << n << "\n"; 
               ast_ll_pp(tout, m_manager, arg); tout << "====>\n"; 
@@ -1373,7 +1373,7 @@ void bv_simplifier_plugin::mk_bv_shl(expr * arg1, expr * arg2, expr_ref & result
     else if (is_num1 && is_num2) {
         SASSERT(r2 < rational(bv_size));
         SASSERT(r2.is_unsigned());
-        result = mk_numeral(r1 * m_util.power_of_two(r2.get_unsigned()), bv_size);
+        result = mk_numeral(r1 * rational::power_of_two(r2.get_unsigned()), bv_size);
     }
 
     //
@@ -1423,7 +1423,7 @@ void bv_simplifier_plugin::mk_bv_lshr(expr * arg1, expr * arg2, expr_ref & resul
     else if (is_num1 && is_num2) {
         SASSERT(r2.is_unsigned());
         unsigned sh = r2.get_unsigned();
-        r1 = div(r1, m_util.power_of_two(sh));
+        r1 = div(r1, rational::power_of_two(sh));
         result = mk_numeral(r1, bv_size);
     }
     //
@@ -1804,8 +1804,8 @@ void bv_simplifier_plugin::mk_bv_rotate_left_core(unsigned shift, numeral r, uns
         result = mk_numeral(r, bv_size);        
     }
     else {
-        rational r1 = div(r, m_util.power_of_two(bv_size - shift)); // shift right
-        rational r2 = (r * m_util.power_of_two(shift)) % m_util.power_of_two(bv_size); // shift left
+        rational r1 = div(r, rational::power_of_two(bv_size - shift)); // shift right
+        rational r2 = (r * rational::power_of_two(shift)) % rational::power_of_two(bv_size); // shift left
         result = mk_numeral(r1 + r2, bv_size);
     }
 }
@@ -1831,8 +1831,8 @@ void bv_simplifier_plugin::mk_bv_rotate_right_core(unsigned shift, numeral r, un
         result = mk_numeral(r, bv_size);
     }
     else {
-        rational r1 = div(r, m_util.power_of_two(shift)); // shift right
-        rational r2 = (r * m_util.power_of_two(bv_size - shift)) % m_util.power_of_two(bv_size); // shift left
+        rational r1 = div(r, rational::power_of_two(shift)); // shift right
+        rational r2 = (r * rational::power_of_two(bv_size - shift)) % rational::power_of_two(bv_size); // shift left
         result = mk_numeral(r1 + r2, bv_size);            
     }
 }
@@ -1935,7 +1935,7 @@ void bv_simplifier_plugin::mk_bv_ashr(expr* arg1, expr* arg2, expr_ref& result)
     else if (is_num1 && is_num2) {
         SASSERT(r2 < rational(bv_size));
         bool   sign = has_sign_bit(r1, bv_size);
-        r1 = div(r1, m_util.power_of_two(r2.get_unsigned()));
+        r1 = div(r1, rational::power_of_two(r2.get_unsigned()));
         if (sign) {
             // pad ones.
             rational p(1);
diff --git a/src/ast/simplifier/bv_simplifier_plugin.h b/src/ast/simplifier/bv_simplifier_plugin.h
index 7f66566b6..36e773de0 100644
--- a/src/ast/simplifier/bv_simplifier_plugin.h
+++ b/src/ast/simplifier/bv_simplifier_plugin.h
@@ -172,7 +172,7 @@ public:
     app * mk_numeral(rational const & n, unsigned bv_size);
     app * mk_numeral(uint64 n, unsigned bv_size) { return mk_numeral(numeral(n, numeral::ui64()), bv_size); }
     app* mk_bv0(unsigned bv_size) { return m_util.mk_numeral(numeral(0), bv_size); }
-    rational mk_allone(unsigned bv_size) { return m_util.power_of_two(bv_size) - numeral(1); }
+    rational mk_allone(unsigned bv_size) { return rational::power_of_two(bv_size) - numeral(1); }
     bool is_minus_one_core(expr * arg) const;
     bool is_x_minus_one(expr * arg, expr * & x);
     void mk_int2bv(expr * arg, sort* range, expr_ref & result);
diff --git a/src/ast/simplifier/simplifier_plugin.h b/src/ast/simplifier/simplifier_plugin.h
index d95547a69..8e176ea6e 100644
--- a/src/ast/simplifier/simplifier_plugin.h
+++ b/src/ast/simplifier/simplifier_plugin.h
@@ -37,7 +37,7 @@ protected:
     void set_reduce_invoked() { m_reduce_invoked = true; }
 
 public:
-    simplifier_plugin(symbol const & fname, ast_manager & m):m_manager(m), m_fid(m.get_family_id(fname)), m_presimp(false), m_reduce_invoked(false) {}
+    simplifier_plugin(symbol const & fname, ast_manager & m):m_manager(m), m_fid(m.mk_family_id(fname)), m_presimp(false), m_reduce_invoked(false) {}
     
     bool reduce_invoked() const { return m_reduce_invoked; }
 
diff --git a/src/ast/static_features.cpp b/src/ast/static_features.cpp
index 234626365..f40eb2c75 100644
--- a/src/ast/static_features.cpp
+++ b/src/ast/static_features.cpp
@@ -23,8 +23,8 @@ static_features::static_features(ast_manager & m):
     m_manager(m),
     m_autil(m),
     m_bfid(m.get_basic_family_id()),
-    m_afid(m.get_family_id("arith")),
-    m_lfid(m.get_family_id("label")),
+    m_afid(m.mk_family_id("arith")),
+    m_lfid(m.mk_family_id("label")),
     m_label_sym("label"),
     m_pattern_sym("pattern"),
     m_expr_list_sym("expr-list") {
diff --git a/src/cmd_context/basic_cmds.cpp b/src/cmd_context/basic_cmds.cpp
index 8f65485ae..c1be7a69b 100644
--- a/src/cmd_context/basic_cmds.cpp
+++ b/src/cmd_context/basic_cmds.cpp
@@ -643,7 +643,7 @@ public:
 
     family_id get_array_fid(cmd_context & ctx) {
         if (m_array_fid == null_family_id) {
-            m_array_fid = ctx.m().get_family_id("array");
+            m_array_fid = ctx.m().mk_family_id("array");
         }
         return m_array_fid;
     }
diff --git a/src/cmd_context/cmd_context.cpp b/src/cmd_context/cmd_context.cpp
index 828cc3a68..043dc45e6 100644
--- a/src/cmd_context/cmd_context.cpp
+++ b/src/cmd_context/cmd_context.cpp
@@ -343,6 +343,13 @@ cmd_context::~cmd_context() {
     m_check_sat_result = 0;
 }
 
+void cmd_context::set_cancel(bool f) {
+    if (m_solver)
+        m_solver->set_cancel(f);
+    if (has_manager())
+        m().set_cancel(f);
+}
+
 void cmd_context::global_params_updated() {
     m_params.updt_params();
     if (m_solver) {
@@ -582,8 +589,8 @@ void cmd_context::init_manager_core(bool new_manager) {
         // it prevents clashes with builtin types.
         insert(pm().mk_plist_decl());
     }
-    if (m_solver) {
-        init_solver_options(m_solver.get());
+    if (m_solver_factory) {
+        mk_solver();
     }
     m_check_logic.set_logic(m(), m_logic);
 }
@@ -1119,7 +1126,7 @@ void cmd_context::reset(bool finalize) {
     reset_func_decls();
     restore_assertions(0);
     if (m_solver)
-        m_solver->reset();
+        m_solver = 0;
     m_pp_env = 0;
     m_dt_eh  = 0;
     if (m_manager) {
@@ -1379,7 +1386,7 @@ void cmd_context::set_diagnostic_stream(char const * name) {
 struct contains_array_op_proc {
     struct found {};
     family_id m_array_fid;
-    contains_array_op_proc(ast_manager & m):m_array_fid(m.get_family_id("array")) {}
+    contains_array_op_proc(ast_manager & m):m_array_fid(m.mk_family_id("array")) {}
     void operator()(var * n)        {}
     void operator()(app * n)        { 
         if (n->get_family_id() != m_array_fid)
@@ -1441,17 +1448,18 @@ void cmd_context::validate_model() {
     }
 }
 
-void cmd_context::init_solver_options(solver * s) {
+void cmd_context::mk_solver() {
+    bool proofs_enabled, models_enabled, unsat_core_enabled;
     params_ref p;
-    m_params.init_solver_params(m(), *m_solver, p);
-    m_solver->init(m(), m_logic);
+    m_params.get_solver_params(m(), p, proofs_enabled, models_enabled, unsat_core_enabled);
+    m_solver = (*m_solver_factory)(m(), p, proofs_enabled, models_enabled, unsat_core_enabled, m_logic);
 }
 
-void cmd_context::set_solver(solver * s) {
+void cmd_context::set_solver_factory(solver_factory * f) {
+    m_solver_factory   = f;
     m_check_sat_result = 0;
-    m_solver = s;
-    if (has_manager() && s != 0) {
-        init_solver_options(s);
+    if (has_manager() && f != 0) {
+        mk_solver();
         // assert formulas and create scopes in the new solver.
         unsigned lim = 0;
         svector<scope>::iterator it  = m_scopes.begin();
diff --git a/src/cmd_context/cmd_context.h b/src/cmd_context/cmd_context.h
index 2edc87ca6..07b0cf456 100644
--- a/src/cmd_context/cmd_context.h
+++ b/src/cmd_context/cmd_context.h
@@ -185,6 +185,7 @@ protected:
     };
 
     svector<scope>               m_scopes;
+    scoped_ptr<solver_factory>   m_solver_factory;
     ref<solver>                  m_solver;
     ref<check_sat_result>        m_check_sat_result;
 
@@ -243,11 +244,14 @@ protected:
     void print_unsupported_msg() { regular_stream() << "unsupported" << std::endl; }
     void print_unsupported_info(symbol const& s) { if (s != symbol::null) diagnostic_stream() << "; " << s << std::endl;}
 
-    void init_solver_options(solver * s);
+    void mk_solver();
 
 public:
     cmd_context(bool main_ctx = true, ast_manager * m = 0, symbol const & l = symbol::null);
     ~cmd_context(); 
+    void set_cancel(bool f);
+    void cancel() { set_cancel(true); }
+    void reset_cancel() { set_cancel(false); }
     context_params  & params() { return m_params; }
     void global_params_updated(); // this method should be invoked when global (and module) params are updated.
     void set_logic(symbol const & s);
@@ -289,8 +293,7 @@ public:
     pdecl_manager & pm() const { if (!m_pmanager) const_cast<cmd_context*>(this)->init_manager(); return *m_pmanager; }
     sexpr_manager & sm() const { if (!m_sexpr_manager) const_cast<cmd_context*>(this)->m_sexpr_manager = alloc(sexpr_manager); return *m_sexpr_manager; }
  
-    void set_solver(solver * s);
-    solver * get_solver() const { return m_solver.get(); }
+    void set_solver_factory(solver_factory * s);
     void set_check_sat_result(check_sat_result * r) { m_check_sat_result = r; }
     check_sat_result * get_check_sat_result() const { return m_check_sat_result.get(); }
     check_sat_state cs_state() const;
diff --git a/src/cmd_context/context_params.cpp b/src/cmd_context/context_params.cpp
index 6d9222a37..2752967dd 100644
--- a/src/cmd_context/context_params.cpp
+++ b/src/cmd_context/context_params.cpp
@@ -131,11 +131,11 @@ params_ref context_params::merge_default_params(params_ref const & p) {
     }
 }
 
-void context_params::init_solver_params(ast_manager & m, solver & s, params_ref const & p) {
-    s.set_produce_proofs(m.proofs_enabled() && m_proof);
-    s.set_produce_models(p.get_bool("model", m_model));
-    s.set_produce_unsat_cores(p.get_bool("unsat_core", m_unsat_core));
-    s.updt_params(merge_default_params(p));
+void context_params::get_solver_params(ast_manager const & m, params_ref & p, bool & proofs_enabled, bool & models_enabled, bool & unsat_core_enabled) {
+    proofs_enabled     = m.proofs_enabled() && p.get_bool("proof", m_proof);
+    models_enabled     = p.get_bool("model", m_model);
+    unsat_core_enabled = p.get_bool("unsat_core", m_unsat_core);
+    p = merge_default_params(p);
 }
 
 ast_manager * context_params::mk_ast_manager() {
diff --git a/src/cmd_context/context_params.h b/src/cmd_context/context_params.h
index dd60b9616..526b4f517 100644
--- a/src/cmd_context/context_params.h
+++ b/src/cmd_context/context_params.h
@@ -22,7 +22,6 @@ Notes:
 
 #include"params.h"
 class ast_manager;
-class solver;
 
 class context_params {
     void set_bool(bool & opt, char const * param, char const * value);
@@ -50,13 +49,9 @@ public:
     */
     
     /**
-       \brief Goodie for updating the solver params
-       based on the configuration of the context_params object.
-
-       This method is used when creating solvers from the
-       cmd_context and API.
+       \brief Goodies for extracting parameters for creating a solver object.
     */
-    void init_solver_params(ast_manager & m, solver & s, params_ref const & p);
+    void get_solver_params(ast_manager const & m, params_ref & p, bool & proofs_enabled, bool & models_enabled, bool & unsat_core_enabled);
 
     /**
        \brief Include in p parameters derived from this context_params.
diff --git a/src/cmd_context/pdecl.cpp b/src/cmd_context/pdecl.cpp
index 6b55d4072..bafd76f0b 100644
--- a/src/cmd_context/pdecl.cpp
+++ b/src/cmd_context/pdecl.cpp
@@ -765,7 +765,7 @@ pdecl_manager::pdecl_manager(ast_manager & m):
     m_allocator(m.get_allocator()),
     m_new_dt_eh(0) {
     m_list = 0;
-    m_datatype_fid = m.get_family_id("datatype");
+    m_datatype_fid = m.mk_family_id("datatype");
 }
 
 pdecl_manager::~pdecl_manager() {
diff --git a/src/math/polynomial/algebraic_numbers.cpp b/src/math/polynomial/algebraic_numbers.cpp
index 90ad6ea9d..804a134e0 100644
--- a/src/math/polynomial/algebraic_numbers.cpp
+++ b/src/math/polynomial/algebraic_numbers.cpp
@@ -2796,72 +2796,58 @@ namespace algebraic_numbers {
     }
 
     void manager::del(numeral & a) {
-        set_cancel(false);
         return m_imp->del(a);
     }
         
     void manager::reset(numeral & a) {
-        set_cancel(false);
         return m_imp->reset(a);
     }
     
     bool manager::is_zero(numeral const & a) {
-        set_cancel(false);
         return m_imp->is_zero(const_cast<numeral&>(a));
     }
 
     bool manager::is_pos(numeral const & a) {
-        set_cancel(false);
         return m_imp->is_pos(const_cast<numeral&>(a));
     }
 
     bool manager::is_neg(numeral const & a) {
-        set_cancel(false);
         return m_imp->is_neg(const_cast<numeral&>(a));
     }
 
     bool manager::is_rational(numeral const & a) {
-        set_cancel(false);
         return m_imp->is_rational(const_cast<numeral&>(a));
     }
 
     bool manager::is_int(numeral const & a) {
-        set_cancel(false);
         return m_imp->is_int(const_cast<numeral&>(a));
     }
 
     unsigned manager::degree(numeral const & a) {
-        set_cancel(false);
         return m_imp->degree(const_cast<numeral&>(a));
     }
 
     void manager::to_rational(numeral const & a, mpq & r) {
-        set_cancel(false);
         return m_imp->to_rational(const_cast<numeral&>(a), r);
     }
 
     void manager::to_rational(numeral const & a, rational & r) {
-        set_cancel(false);
         return m_imp->to_rational(const_cast<numeral&>(a), r);
     }
     
     void manager::swap(numeral & a, numeral & b) {
-        set_cancel(false);
         return m_imp->swap(a, b);
     }
 
     void manager::int_lt(numeral const & a, numeral & b) {
-        set_cancel(false);
         m_imp->int_lt(const_cast<numeral&>(a), b);
     }
 
     void manager::int_gt(numeral const & a, numeral & b) {
-        set_cancel(false);
         m_imp->int_gt(const_cast<numeral&>(a), b);
     }
 
     void manager::select(numeral const & prev, numeral const & curr, numeral & result) {
-        set_cancel(false);
         m_imp->select(const_cast<numeral&>(prev), const_cast<numeral&>(curr), result);
     }
 
@@ -2878,55 +2864,45 @@ namespace algebraic_numbers {
     }
     
     void manager::set(numeral & a, mpq const & n) {
-        set_cancel(false);
         m_imp->set(a, n);
     }
 
     void manager::set(numeral & a, numeral const & n) {
-        set_cancel(false);
         m_imp->set(a, n);
     }
         
     void manager::isolate_roots(polynomial_ref const & p, numeral_vector & roots) {
-        set_cancel(false);
         m_imp->isolate_roots(p, roots);
     }
 
     void manager::isolate_roots(polynomial_ref const & p, polynomial::var2anum const & x2v, numeral_vector & roots) {
-        set_cancel(false);
         m_imp->isolate_roots(p, x2v, roots);
     }
 
     void manager::isolate_roots(polynomial_ref const & p, polynomial::var2anum const & x2v, numeral_vector & roots, svector<int> & signs) {
-        set_cancel(false);
         m_imp->isolate_roots(p, x2v, roots, signs);
     }
 
     void manager::mk_root(polynomial_ref const & p, unsigned i, numeral & r) {
-        set_cancel(false);
         m_imp->mk_root(p, i, r);
     }
 
     void manager::mk_root(sexpr const * p, unsigned i, numeral & r) {
-        set_cancel(false);
         m_imp->mk_root(p, i, r);
     }
         
     void manager::root(numeral const & a, unsigned k, numeral & b) {
-        set_cancel(false);
         m_imp->root(const_cast<numeral&>(a), k, b);
     }
 
     void manager::power(numeral const & a, unsigned k, numeral & b) {
         TRACE("anum_detail", display_root(tout, a); tout << "^" << k << "\n";);
-        set_cancel(false);
         m_imp->power(const_cast<numeral&>(a), k, b);
         TRACE("anum_detail", tout << "^ result: "; display_root(tout, b); tout << "\n";);
     }
 
     void manager::add(numeral const & a, numeral const & b, numeral & c) {
         TRACE("anum_detail", display_root(tout, a); tout << " + "; display_root(tout, b); tout << "\n";);
-        set_cancel(false);
         m_imp->add(const_cast<numeral&>(a), const_cast<numeral&>(b), c);
         TRACE("anum_detail", tout << "+ result: "; display_root(tout, c); tout << "\n";);
     }
@@ -2939,45 +2915,37 @@ namespace algebraic_numbers {
 
     void manager::sub(numeral const & a, numeral const & b, numeral & c) {
         TRACE("anum_detail", display_root(tout, a); tout << " - "; display_root(tout, b); tout << "\n";);
-        set_cancel(false);
         m_imp->sub(const_cast<numeral&>(a), const_cast<numeral&>(b), c);
         TRACE("anum_detail", tout << "- result: "; display_root(tout, c); tout << "\n";);
     }
 
     void manager::mul(numeral const & a, numeral const & b, numeral & c) {
         TRACE("anum_detail", display_root(tout, a); tout << " * "; display_root(tout, b); tout << "\n";);
-        set_cancel(false);
         m_imp->mul(const_cast<numeral&>(a), const_cast<numeral&>(b), c);
         TRACE("anum_detail", tout << "* result: "; display_root(tout, c); tout << "\n";);
     }
 
     void manager::div(numeral const & a, numeral const & b, numeral & c) {
-        set_cancel(false);
         m_imp->div(const_cast<numeral&>(a), const_cast<numeral&>(b), c);
     }
 
     void manager::neg(numeral & a) {
-        set_cancel(false);
         m_imp->neg(a);
     }
 
     void manager::inv(numeral & a) {
-        set_cancel(false);
         m_imp->inv(a);
     }
 
     int manager::compare(numeral const & a, numeral const & b) {
-        set_cancel(false);
         return m_imp->compare(const_cast<numeral&>(a), const_cast<numeral&>(b));
     }
 
     bool manager::eq(numeral const & a, numeral const & b) {
-        set_cancel(false);
         return m_imp->eq(const_cast<numeral&>(a), const_cast<numeral&>(b));
     }
     
     bool manager::eq(numeral const & a, mpq const & b) {
-        set_cancel(false);
         return m_imp->eq(const_cast<numeral&>(a), b);
     }
 
@@ -2988,12 +2956,10 @@ namespace algebraic_numbers {
     }
 
     bool manager::lt(numeral const & a, numeral const & b) {
-        set_cancel(false);
         return m_imp->lt(const_cast<numeral&>(a), const_cast<numeral&>(b));
     }
     
     bool manager::lt(numeral const & a, mpq const & b) {
-        set_cancel(false);
         return m_imp->lt(const_cast<numeral&>(a), b);
     }
 
@@ -3004,7 +2970,6 @@ namespace algebraic_numbers {
     }
 
     bool manager::gt(numeral const & a, mpq const & b) {
-        set_cancel(false);
         return m_imp->gt(const_cast<numeral&>(a), b);
     }
 
@@ -3073,38 +3038,31 @@ namespace algebraic_numbers {
     }
 
     int manager::eval_sign_at(polynomial_ref const & p, polynomial::var2anum const & x2v) {
-        set_cancel(false);
         SASSERT(&(x2v.m()) == this);
         return m_imp->eval_sign_at(p, x2v);
     }
 
     void manager::display_interval(std::ostream & out, numeral const & a) const {
-        const_cast<manager*>(this)->set_cancel(false);
         m_imp->display_interval(out, a);
     }
 
     void manager::display_decimal(std::ostream & out, numeral const & a, unsigned precision) const {
-        const_cast<manager*>(this)->set_cancel(false);
         m_imp->display_decimal(out, a, precision);
     }
 
     void manager::display_root(std::ostream & out, numeral const & a) const {
-        const_cast<manager*>(this)->set_cancel(false);
         m_imp->display_root(out, a);
     }
 
     void manager::display_mathematica(std::ostream & out, numeral const & a) const {
-        const_cast<manager*>(this)->set_cancel(false);
         m_imp->display_mathematica(out, a);
     }
 
     void manager::display_root_smt2(std::ostream & out, numeral const & a) const {
-        const_cast<manager*>(this)->set_cancel(false);
         m_imp->display_root_smt2(out, a);
     }
 
     void manager::reset_statistics() {
-        set_cancel(false);
         m_imp->reset_statistics();
     }
         
diff --git a/src/math/polynomial/algebraic_numbers.h b/src/math/polynomial/algebraic_numbers.h
index a4669eae6..d11237b86 100644
--- a/src/math/polynomial/algebraic_numbers.h
+++ b/src/math/polynomial/algebraic_numbers.h
@@ -64,8 +64,8 @@ namespace algebraic_numbers {
         static void collect_param_descrs(param_descrs & r) { get_param_descrs(r); }
 
         void set_cancel(bool f);
-        
         void cancel() { set_cancel(true); }
+        void reset_cancel() { set_cancel(false); }
 
         void updt_params(params_ref const & p);
 
diff --git a/src/math/polynomial/polynomial.cpp b/src/math/polynomial/polynomial.cpp
index 4e14c5661..f5d96e740 100644
--- a/src/math/polynomial/polynomial.cpp
+++ b/src/math/polynomial/polynomial.cpp
@@ -2368,7 +2368,6 @@ namespace polynomial {
 
         void checkpoint() {
             if (m_cancel) {
-                set_cancel(false);
                 throw polynomial_exception("canceled");
             }
             cooperate("polynomial");
diff --git a/src/math/polynomial/polynomial.h b/src/math/polynomial/polynomial.h
index d17d2ac5a..e52dd4fee 100644
--- a/src/math/polynomial/polynomial.h
+++ b/src/math/polynomial/polynomial.h
@@ -220,6 +220,7 @@ namespace polynomial {
 
         void set_cancel(bool f);
         void cancel() { set_cancel(true); }
+        void reset_cancel() { set_cancel(false); }
 
         /**
            \brief Abstract event handler.
diff --git a/src/math/polynomial/polynomial_factorization.cpp b/src/math/polynomial/polynomial_factorization.cpp
index e0f050411..220048a9a 100644
--- a/src/math/polynomial/polynomial_factorization.cpp
+++ b/src/math/polynomial/polynomial_factorization.cpp
@@ -16,7 +16,7 @@ Author:
 Notes:
 
    [1] Elwyn Ralph Berlekamp. Factoring Polynomials over Finite Fields. Bell System Technical Journal, 
-       46(8-10):1853–1859, 1967.
+       46(8-10):1853-1859, 1967.
    [2] Donald Ervin Knuth. The Art of Computer Programming, volume 2: Seminumerical Algorithms. Addison Wesley, third 
        edition, 1997.
    [3] Henri Cohen. A Course in Computational Algebraic Number Theory. Springer Verlag, 1993.
diff --git a/src/math/polynomial/polynomial_factorization.h b/src/math/polynomial/polynomial_factorization.h
index 48b4efd98..f069121ba 100644
--- a/src/math/polynomial/polynomial_factorization.h
+++ b/src/math/polynomial/polynomial_factorization.h
@@ -16,7 +16,7 @@ Author:
 Notes:
 
    [1] Elwyn Ralph Berlekamp. Factoring Polynomials over Finite Fields. Bell System Technical Journal, 
-       46(8-10):1853–1859, 1967.
+       46(8-10):1853-1859, 1967.
    [2] Donald Ervin Knuth. The Art of Computer Programming, volume 2: Seminumerical Algorithms. Addison Wesley, third 
        edition, 1997.
    [3] Henri Cohen. A Course in Computational Algebraic Number Theory. Springer Verlag, 1993.
diff --git a/src/math/polynomial/upolynomial_factorization.cpp b/src/math/polynomial/upolynomial_factorization.cpp
index a1e28e727..230d352f3 100644
--- a/src/math/polynomial/upolynomial_factorization.cpp
+++ b/src/math/polynomial/upolynomial_factorization.cpp
@@ -16,7 +16,7 @@ Author:
 Notes:
 
    [1] Elwyn Ralph Berlekamp. Factoring Polynomials over Finite Fields. Bell System Technical Journal, 
-       46(8-10):1853–1859, 1967.
+       46(8-10):1853-1859, 1967.
    [2] Donald Ervin Knuth. The Art of Computer Programming, volume 2: Seminumerical Algorithms. Addison Wesley, third 
        edition, 1997.
    [3] Henri Cohen. A Course in Computational Algebraic Number Theory. Springer Verlag, 1993.
diff --git a/src/math/polynomial/upolynomial_factorization.h b/src/math/polynomial/upolynomial_factorization.h
index e687786da..327fffc9c 100644
--- a/src/math/polynomial/upolynomial_factorization.h
+++ b/src/math/polynomial/upolynomial_factorization.h
@@ -16,7 +16,7 @@ Author:
 Notes:
 
    [1] Elwyn Ralph Berlekamp. Factoring Polynomials over Finite Fields. Bell System Technical Journal, 
-       46(8-10):1853–1859, 1967.
+       46(8-10):1853-1859, 1967.
    [2] Donald Ervin Knuth. The Art of Computer Programming, volume 2: Seminumerical Algorithms. Addison Wesley, third 
        edition, 1997.
    [3] Henri Cohen. A Course in Computational Algebraic Number Theory. Springer Verlag, 1993.
diff --git a/src/math/polynomial/upolynomial_factorization_int.h b/src/math/polynomial/upolynomial_factorization_int.h
index c076b2e6d..92d62301d 100644
--- a/src/math/polynomial/upolynomial_factorization_int.h
+++ b/src/math/polynomial/upolynomial_factorization_int.h
@@ -17,7 +17,7 @@ Author:
 Notes:
 
    [1] Elwyn Ralph Berlekamp. Factoring Polynomials over Finite Fields. Bell System Technical Journal, 
-       46(8-10):1853–1859, 1967.
+       46(8-10):1853-1859, 1967.
    [2] Donald Ervin Knuth. The Art of Computer Programming, volume 2: Seminumerical Algorithms. Addison Wesley, third 
        edition, 1997.
    [3] Henri Cohen. A Course in Computational Algebraic Number Theory. Springer Verlag, 1993.
diff --git a/src/model/model_evaluator.cpp b/src/model/model_evaluator.cpp
index beed0061e..dc4c20aa8 100644
--- a/src/model/model_evaluator.cpp
+++ b/src/model/model_evaluator.cpp
@@ -244,10 +244,10 @@ unsigned model_evaluator::get_num_steps() const {
     return m_imp->get_num_steps();
 }
 
-void model_evaluator::cancel() {
+void model_evaluator::set_cancel(bool f) {
     #pragma omp critical (model_evaluator)
     {
-        m_imp->cancel();
+        m_imp->set_cancel(f);
     }
 }
 
diff --git a/src/model/model_evaluator.h b/src/model/model_evaluator.h
index aad06739b..1a7469c6c 100644
--- a/src/model/model_evaluator.h
+++ b/src/model/model_evaluator.h
@@ -41,7 +41,9 @@ public:
 
     void operator()(expr * t, expr_ref & r);
 
-    void cancel();
+    void set_cancel(bool f);
+    void cancel() { set_cancel(true); }
+    void reset_cancel() { set_cancel(false); }
     void cleanup(params_ref const & p = params_ref());
     void reset(params_ref const & p = params_ref());
     
diff --git a/src/muz_qe/dl_bmc_engine.cpp b/src/muz_qe/dl_bmc_engine.cpp
index b5ffa808a..c7e53e581 100644
--- a/src/muz_qe/dl_bmc_engine.cpp
+++ b/src/muz_qe/dl_bmc_engine.cpp
@@ -963,7 +963,7 @@ namespace datalog {
             
             
             sort_ref_vector new_sorts(m);
-            family_id dfid = m.get_family_id("datatype");
+            family_id dfid = m.mk_family_id("datatype");
             datatype_decl_plugin* dtp = static_cast<datatype_decl_plugin*>(m.get_plugin(dfid));
             VERIFY (dtp->mk_datatypes(dts.size(), dts.c_ptr(), new_sorts));
             
diff --git a/src/muz_qe/dl_cmds.cpp b/src/muz_qe/dl_cmds.cpp
index bf9c24203..c88e7346e 100644
--- a/src/muz_qe/dl_cmds.cpp
+++ b/src/muz_qe/dl_cmds.cpp
@@ -75,7 +75,7 @@ struct dl_context {
         if (!m_decl_plugin) {
             symbol name("datalog_relation");
             if (m.has_plugin(name)) {
-                m_decl_plugin = static_cast<datalog::dl_decl_plugin*>(m_cmd.m().get_plugin(m.get_family_id(name)));
+                m_decl_plugin = static_cast<datalog::dl_decl_plugin*>(m_cmd.m().get_plugin(m.mk_family_id(name)));
             }
             else {
                 m_decl_plugin = alloc(datalog::dl_decl_plugin);
diff --git a/src/muz_qe/dl_context.h b/src/muz_qe/dl_context.h
index f84050e68..d3309beb5 100644
--- a/src/muz_qe/dl_context.h
+++ b/src/muz_qe/dl_context.h
@@ -349,6 +349,7 @@ namespace datalog {
         void cancel();
 
         void cleanup();
+        void reset_cancel() { cleanup(); }
 
         /**
            \brief check if query 'q' is satisfied under asserted rules and background.
diff --git a/src/muz_qe/dl_mk_extract_quantifiers2.cpp b/src/muz_qe/dl_mk_extract_quantifiers2.cpp
index 97976a6be..58255d2a1 100644
--- a/src/muz_qe/dl_mk_extract_quantifiers2.cpp
+++ b/src/muz_qe/dl_mk_extract_quantifiers2.cpp
@@ -332,7 +332,7 @@ namespace datalog {
         smt::quantifier_manager* qm = ctx.get_quantifier_manager();
         qm->get_plugin()->set_instance_plugin(alloc(instance_plugin, *this));
 #endif
-        lbool res = solver.check();
+        solver.check();
 
         for (unsigned i = 0; i < m_bindings.size(); ++i) {
             expr_ref_vector& binding = m_bindings[i];
diff --git a/src/muz_qe/dl_relation_manager.h b/src/muz_qe/dl_relation_manager.h
index 270e06f12..ecba3d598 100644
--- a/src/muz_qe/dl_relation_manager.h
+++ b/src/muz_qe/dl_relation_manager.h
@@ -3,7 +3,7 @@ Copyright (c) 2006 Microsoft Corporation
 
 Module Name:
 
-    dl_remation_manager.h
+    dl_relation_manager.h
 
 Abstract:
 
@@ -316,7 +316,7 @@ namespace datalog {
                 oldTgt:=tgt.clone();
                 tgt:=tgt \union src
                 if(tgt!=oldTgt) {
-                    delta:=delta \union src    //also “delta \union tgt” would work
+                    delta:=delta \union src    //also ?delta \union tgt? would work
                 }
             }
 
@@ -488,7 +488,7 @@ namespace datalog {
                 oldTgt:=tgt.clone();
                 tgt:=tgt \union src
                 if(tgt!=oldTgt) {
-                    delta:=delta \union src    //also “delta \union tgt” would work
+                    delta:=delta \union src    //also ?delta \union tgt? would work
                 }
             }
 
diff --git a/src/muz_qe/dl_rule.cpp b/src/muz_qe/dl_rule.cpp
index bd7131fea..d34f8a67f 100644
--- a/src/muz_qe/dl_rule.cpp
+++ b/src/muz_qe/dl_rule.cpp
@@ -74,7 +74,7 @@ namespace datalog {
     class remove_label_cfg : public default_rewriter_cfg {
         family_id m_label_fid;
     public:        
-        remove_label_cfg(ast_manager& m): m_label_fid(m.get_family_id("label")) {}
+        remove_label_cfg(ast_manager& m): m_label_fid(m.get_label_family_id()) {}
         virtual ~remove_label_cfg() {}
 
         br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, 
diff --git a/src/muz_qe/pdr_util.cpp b/src/muz_qe/pdr_util.cpp
index fd08b1aad..1ea705e6e 100644
--- a/src/muz_qe/pdr_util.cpp
+++ b/src/muz_qe/pdr_util.cpp
@@ -1129,7 +1129,11 @@ namespace pdr {
             if (a.is_numeral(lhs) || a.is_numeral(rhs)) {
                 return test_ineq(e);
             }
-            return test_term(lhs) && test_term(rhs);
+            return 
+                test_term(lhs) && 
+                test_term(rhs) &&
+                !a.is_mul(lhs) &&
+                !a.is_mul(rhs);
         }
 
         bool test_term(expr* e) const {
diff --git a/src/muz_qe/proof_utils.cpp b/src/muz_qe/proof_utils.cpp
index 75c9cbb15..e5a3ea437 100644
--- a/src/muz_qe/proof_utils.cpp
+++ b/src/muz_qe/proof_utils.cpp
@@ -312,9 +312,10 @@ public:
 };
 
 void proof_utils::reduce_hypotheses(proof_ref& pr) {
-    class reduce_hypotheses reduce(pr.get_manager());
+    ast_manager& m = pr.get_manager();
+    class reduce_hypotheses reduce(m);
     reduce(pr);
-    SASSERT(is_closed(pr.get_manager(), pr));
+    CTRACE("proof_utils", !is_closed(m, pr), tout << mk_pp(pr, m) << "\n";);
 }
 
 class proof_is_closed {
@@ -449,7 +450,7 @@ static void permute_unit_resolution(expr_ref_vector& refs, obj_map<proof,proof*>
         parameter const* params = thLemma->get_decl()->get_parameters();
         unsigned num_params = thLemma->get_decl()->get_num_parameters();
         SASSERT(params[0].is_symbol());
-        family_id tid = m.get_family_id(params[0].get_symbol());
+        family_id tid = m.mk_family_id(params[0].get_symbol());
         SASSERT(tid != null_family_id);
         prNew = m.mk_th_lemma(tid, m.get_fact(pr), 
                               premises.size(), premises.c_ptr(), num_params-1, params+1);
diff --git a/src/muz_qe/qe_arith_plugin.cpp b/src/muz_qe/qe_arith_plugin.cpp
index 69c036639..4e158229b 100644
--- a/src/muz_qe/qe_arith_plugin.cpp
+++ b/src/muz_qe/qe_arith_plugin.cpp
@@ -1512,7 +1512,7 @@ public:
 
     public:
         arith_plugin(i_solver_context& ctx, ast_manager& m, smt_params& p): 
-            qe_solver_plugin(m, m.get_family_id("arith"), ctx),
+            qe_solver_plugin(m, m.mk_family_id("arith"), ctx),
             m_util(m, p, ctx),
             m_trail(m)
         {}
@@ -2403,7 +2403,7 @@ public:
         bool                         m_produce_models;
     public:
         nlarith_plugin(i_solver_context& ctx, ast_manager& m, bool produce_models) : 
-            qe_solver_plugin(m, m.get_family_id("arith"), ctx),
+            qe_solver_plugin(m, m.mk_family_id("arith"), ctx),
             m_rewriter(m),
             m_util(m),
             m_replacer(mk_default_expr_replacer(m)),
diff --git a/src/muz_qe/qe_array_plugin.cpp b/src/muz_qe/qe_array_plugin.cpp
index c013f93f4..106a42338 100644
--- a/src/muz_qe/qe_array_plugin.cpp
+++ b/src/muz_qe/qe_array_plugin.cpp
@@ -16,7 +16,7 @@ namespace qe {
     public:
 
         array_plugin(i_solver_context& ctx, ast_manager& m) : 
-            qe_solver_plugin(m, m.get_family_id("array"), ctx),
+            qe_solver_plugin(m, m.mk_family_id("array"), ctx),
             m_replace(mk_default_expr_replacer(m))
         {
         }
diff --git a/src/muz_qe/qe_bv_plugin.cpp b/src/muz_qe/qe_bv_plugin.cpp
index 8712061d6..cae567111 100644
--- a/src/muz_qe/qe_bv_plugin.cpp
+++ b/src/muz_qe/qe_bv_plugin.cpp
@@ -32,7 +32,7 @@ namespace qe {
         bv_util      m_bv;
     public:
         bv_plugin(i_solver_context& ctx, ast_manager& m): 
-            qe_solver_plugin(m, m.get_family_id("bv"), ctx),
+            qe_solver_plugin(m, m.mk_family_id("bv"), ctx),
             m_replace(mk_default_expr_replacer(m)),
             m_bv(m)
         {}
diff --git a/src/muz_qe/qe_datatype_plugin.cpp b/src/muz_qe/qe_datatype_plugin.cpp
index 3978a9ba4..0b51f26af 100644
--- a/src/muz_qe/qe_datatype_plugin.cpp
+++ b/src/muz_qe/qe_datatype_plugin.cpp
@@ -422,7 +422,7 @@ namespace qe {
 
     public:
         datatype_plugin(i_solver_context& ctx, ast_manager& m) : 
-            qe_solver_plugin(m, m.get_family_id("datatype"), ctx),
+            qe_solver_plugin(m, m.mk_family_id("datatype"), ctx),
             m_datatype_util(m),
             m_replace(mk_default_expr_replacer(m)),
             m_trail(m)
diff --git a/src/muz_qe/qe_dl_plugin.cpp b/src/muz_qe/qe_dl_plugin.cpp
index 23f43759d..15e972e88 100644
--- a/src/muz_qe/qe_dl_plugin.cpp
+++ b/src/muz_qe/qe_dl_plugin.cpp
@@ -45,7 +45,7 @@ namespace qe {
         
     public:
         dl_plugin(i_solver_context& ctx, ast_manager& m) : 
-            qe_solver_plugin(m, m.get_family_id("datalog_relation"), ctx),
+            qe_solver_plugin(m, m.mk_family_id("datalog_relation"), ctx),
             m_replace(mk_default_expr_replacer(m)),
             m_util(m),
             m_trail(m)
diff --git a/src/muz_qe/qe_lite.cpp b/src/muz_qe/qe_lite.cpp
index 8880a9ba5..df4a55475 100644
--- a/src/muz_qe/qe_lite.cpp
+++ b/src/muz_qe/qe_lite.cpp
@@ -35,7 +35,7 @@ Revision History:
 #include "dl_util.h"
 #include "for_each_expr.h"
 #include "expr_safe_replace.h"
-
+#include "cooperate.h"
 
 class is_variable_proc {
 public:
@@ -91,6 +91,7 @@ namespace eq {
         expr_ref_vector  m_subst_map;
         expr_ref_buffer  m_new_args;
         th_rewriter      m_rewriter;
+        volatile bool    m_cancel;
         
         void der_sort_vars(ptr_vector<var> & vars, ptr_vector<expr> & definitions, unsigned_vector & order) {
             order.reset();
@@ -530,6 +531,7 @@ namespace eq {
             
             // Find all definitions
             for (unsigned i = 0; i < num_args; i++) {
+                checkpoint();
                 if (is_var_def(is_exists, args[i], v, t)) {
                     unsigned idx = v->get_idx();
                     if(m_map.get(idx, 0) == 0) {
@@ -569,8 +571,14 @@ namespace eq {
             return false;
         }
 
+        void checkpoint() {
+            cooperate("der");
+            if (m_cancel)
+                throw tactic_exception(TACTIC_CANCELED_MSG);
+        }
+
     public:
-        der(ast_manager & m): m(m), a(m), m_is_variable(0), m_subst(m), m_new_exprs(m), m_subst_map(m), m_new_args(m), m_rewriter(m) {}
+        der(ast_manager & m): m(m), a(m), m_is_variable(0), m_subst(m), m_new_exprs(m), m_subst_map(m), m_new_args(m), m_rewriter(m), m_cancel(false) {}
         
         void set_is_variable_proc(is_variable_proc& proc) { m_is_variable = &proc;}
         
@@ -588,6 +596,7 @@ namespace eq {
             r = q;
             // Keep applying reduce_quantifier1 until r doesn't change anymore
             do {
+                checkpoint();
                 proof_ref curr_pr(m);
                 q  = to_quantifier(r);
                 reduce_quantifier1(q, r, curr_pr);
@@ -605,6 +614,12 @@ namespace eq {
         }
         
         ast_manager& get_manager() const { return m; }
+
+        void set_cancel(bool f) {
+            m_rewriter.set_cancel(f);
+            m_cancel = f;
+        }
+
     };
 }; // namespace eq
 
@@ -618,6 +633,7 @@ namespace ar {
         is_variable_proc*        m_is_variable;
         ptr_vector<expr>         m_todo;
         expr_mark                m_visited;
+        volatile bool            m_cancel;
         
         bool is_variable(expr * e) const {
             return (*m_is_variable)(e);
@@ -723,13 +739,19 @@ namespace ar {
             return false;
         }
 
+        void checkpoint() {
+            cooperate("der");
+            if (m_cancel)
+                throw tactic_exception(TACTIC_CANCELED_MSG);
+        }
 
     public:
 
-        der(ast_manager& m): m(m), a(m), m_is_variable(0) {}
+        der(ast_manager& m): m(m), a(m), m_is_variable(0), m_cancel(false) {}
 
         void operator()(expr_ref_vector& fmls) {
             for (unsigned i = 0; i < fmls.size(); ++i) {
+                checkpoint();
                 solve_select(fmls, i, fmls[i].get());
                 solve_neq_select(fmls, i, fmls[i].get());
             }
@@ -738,6 +760,10 @@ namespace ar {
         void operator()(expr* e) {}
 
         void set_is_variable_proc(is_variable_proc& proc) { m_is_variable = &proc;}
+
+        void set_cancel(bool f) {
+            m_cancel = f;
+        }
         
     };
 }; // namespace ar
@@ -866,7 +892,6 @@ namespace fm {
         unsigned                 m_fm_cutoff2;
         unsigned                 m_fm_extra;
         bool                     m_fm_occ;
-        unsigned long long       m_max_memory;
         unsigned                 m_counter;
         bool                     m_inconsistent;
         expr_dependency_ref      m_inconsistent_core;
@@ -1243,7 +1268,7 @@ namespace fm {
         //
         // ---------------------------
         
-        fm(ast_manager & _m, params_ref const & p):
+        fm(ast_manager & _m):
             m(_m),
             m_allocator("fm-elim"),
             m_util(m),
@@ -1251,7 +1276,6 @@ namespace fm {
             m_var2expr(m),
             m_new_fmls(m),
             m_inconsistent_core(m) {
-            updt_params(p);
             m_cancel = false;
         }
         
@@ -1259,14 +1283,13 @@ namespace fm {
             reset_constraints();
         }
         
-        void updt_params(params_ref const & p) {
-            m_max_memory     = megabytes_to_bytes(p.get_uint("max_memory", UINT_MAX));
-            m_fm_real_only   = p.get_bool("fm_real_only", true);
-            m_fm_limit       = p.get_uint("fm_limit", 5000000);
-            m_fm_cutoff1     = p.get_uint("fm_cutoff1", 8);
-            m_fm_cutoff2     = p.get_uint("fm_cutoff2", 256);
-            m_fm_extra       = p.get_uint("fm_extra", 0);
-            m_fm_occ         = p.get_bool("fm_occ", false);
+        void updt_params() {
+            m_fm_real_only   = true;
+            m_fm_limit       = 5000000;
+            m_fm_cutoff1     = 8;
+            m_fm_cutoff2     = 256;
+            m_fm_extra       = 0;
+            m_fm_occ         = false;
         }
         
         void set_cancel(bool f) {
@@ -2010,11 +2033,9 @@ namespace fm {
         }
         
         void checkpoint() {
-            // cooperate("fm");
+            cooperate("fm");
             if (m_cancel)
                 throw tactic_exception(TACTIC_CANCELED_MSG);
-            if (memory::get_allocation_size() > m_max_memory)
-                throw tactic_exception(TACTIC_MAX_MEMORY_MSG);
         }
     public:
 
@@ -2083,11 +2104,56 @@ namespace fm {
 } // namespace fm
 
 class qe_lite::impl {
+public:
+    struct elim_cfg : public default_rewriter_cfg {
+        impl& m_imp;
+        ast_manager& m;
+    public:
+        elim_cfg(impl& i): m_imp(i), m(i.m) {}
+        
+        bool reduce_quantifier(quantifier * q, 
+                               expr * new_body, 
+                               expr * const * new_patterns, 
+                               expr * const * new_no_patterns,
+                               expr_ref & result,
+                               proof_ref & result_pr) {
+            result = new_body;
+            if (is_forall(q)) {
+                result = m.mk_not(result);
+            }
+            uint_set indices;
+            for (unsigned i = 0; i < q->get_num_decls(); ++i) {
+                indices.insert(i);
+            }
+            m_imp(indices, true, result);          
+            if (is_forall(q)) {
+                result = m.mk_not(result);
+            }
+            result = m.update_quantifier(
+                q, 
+                q->get_num_patterns(), new_patterns, 
+                q->get_num_no_patterns(), new_no_patterns, result);
+            m_imp.m_rewriter(result);
+            return true;
+        }
+    };
+
+    class elim_star : public rewriter_tpl<elim_cfg> {
+        elim_cfg m_cfg;
+    public:
+        elim_star(impl& i): 
+            rewriter_tpl<elim_cfg>(i.m, false, m_cfg),
+            m_cfg(i)
+        {}
+    };
+
+private:
     ast_manager& m;
-    params_ref   m_params;
     eq::der      m_der;
     fm::fm       m_fm;
     ar::der      m_array_der;
+    elim_star    m_elim_star;
+    th_rewriter  m_rewriter;
 
     bool has_unique_non_ground(expr_ref_vector const& fmls, unsigned& index) {
         index = fmls.size();
@@ -2106,7 +2172,13 @@ class qe_lite::impl {
     }
 
 public:
-    impl(ast_manager& m): m(m), m_der(m), m_fm(m, m_params), m_array_der(m) {}
+    impl(ast_manager& m): 
+        m(m), 
+        m_der(m), 
+        m_fm(m), 
+        m_array_der(m), 
+        m_elim_star(*this), 
+        m_rewriter(m) {}
     
     void operator()(app_ref_vector& vars, expr_ref& fml) {
         if (vars.empty()) {
@@ -2145,14 +2217,12 @@ public:
         else {
             fml = tmp;
         }
-    }
+    }    
 
     void operator()(expr_ref& fml, proof_ref& pr) {
-        // TODO apply der everywhere as a rewriting rule.
-        // TODO add cancel method.
-        if (is_quantifier(fml)) {
-            m_der(to_quantifier(fml), fml, pr);
-        }
+        expr_ref tmp(m);
+        m_elim_star(fml, tmp, pr);
+        fml = tmp;
     }
 
     void operator()(uint_set const& index_set, bool index_of_bound, expr_ref& fml) {
@@ -2195,6 +2265,14 @@ public:
         TRACE("qe_lite", for (unsigned i = 0; i < fmls.size(); ++i) tout << mk_pp(fmls[i].get(), m) << "\n";);
     }
 
+    void set_cancel(bool f) {
+        m_der.set_cancel(f);
+        m_array_der.set_cancel(f);
+        m_fm.set_cancel(f);
+        m_elim_star.set_cancel(f);
+        m_rewriter.set_cancel(f);
+    }
+
 };
 
 qe_lite::qe_lite(ast_manager& m) {
@@ -2209,6 +2287,10 @@ void qe_lite::operator()(app_ref_vector& vars, expr_ref& fml) {
     (*m_impl)(vars, fml);
 }
 
+void qe_lite::set_cancel(bool f) {
+    m_impl->set_cancel(f);
+}
+
 void qe_lite::operator()(expr_ref& fml, proof_ref& pr) {
     (*m_impl)(fml, pr);
 }
@@ -2220,3 +2302,130 @@ void qe_lite::operator()(uint_set const& index_set, bool index_of_bound, expr_re
 void qe_lite::operator()(uint_set const& index_set, bool index_of_bound, expr_ref_vector& fmls) {
     (*m_impl)(index_set, index_of_bound, fmls);
 }
+
+class qe_lite_tactic : public tactic {
+    
+    struct imp {
+        ast_manager&             m;
+        qe_lite                  m_qe;
+        volatile bool            m_cancel;
+
+        imp(ast_manager& m, params_ref const& p): 
+            m(m),
+            m_qe(m),
+            m_cancel(false)
+        {}
+
+        void set_cancel(bool f) {
+            m_cancel = f;
+            m_qe.set_cancel(f);
+        }
+
+        void checkpoint() {
+            if (m_cancel)
+                throw tactic_exception(TACTIC_CANCELED_MSG);
+            cooperate("qe-lite");
+        }
+        
+        void operator()(goal_ref const & g, 
+                        goal_ref_buffer & result, 
+                        model_converter_ref & mc, 
+                        proof_converter_ref & pc,
+                        expr_dependency_ref & core) {
+            SASSERT(g->is_well_sorted());
+            mc = 0; pc = 0; core = 0;
+            tactic_report report("qe-lite", *g);
+            proof_ref new_pr(m);
+            expr_ref new_f(m);
+            bool produce_proofs = g->proofs_enabled();
+
+            unsigned sz = g->size();
+            for (unsigned i = 0; i < sz; i++) {
+                checkpoint();
+                if (g->inconsistent())
+                    break;
+                expr * f = g->form(i);
+                if (!has_quantifiers(f))
+                    continue;
+                new_f = f;
+                m_qe(new_f, new_pr);
+                if (produce_proofs) {
+                    new_pr = m.mk_modus_ponens(g->pr(i), new_pr);
+                }
+                g->update(i, new_f, new_pr, g->dep(i));                
+            }
+            g->inc_depth();
+            result.push_back(g.get());
+            TRACE("qe", g->display(tout););
+            SASSERT(g->is_well_sorted());
+        }
+
+    };
+    
+    params_ref m_params;
+    imp *      m_imp;
+
+public:
+    qe_lite_tactic(ast_manager & m, params_ref const & p):
+        m_params(p) {
+        m_imp = alloc(imp, m, p);
+    }
+
+    virtual tactic * translate(ast_manager & m) {
+        return alloc(qe_lite_tactic, m, m_params);
+    }
+        
+    virtual ~qe_lite_tactic() {
+        dealloc(m_imp);
+    }
+
+    virtual void updt_params(params_ref const & p) {
+        m_params = p;
+        // m_imp->updt_params(p);
+    }
+
+   
+    virtual void collect_param_descrs(param_descrs & r) {
+        // m_imp->collect_param_descrs(r);
+    }
+    
+    virtual void operator()(goal_ref const & in, 
+                            goal_ref_buffer & result, 
+                            model_converter_ref & mc, 
+                            proof_converter_ref & pc,
+                            expr_dependency_ref & core) {
+        (*m_imp)(in, result, mc, pc, core);
+    }
+
+    
+    virtual void collect_statistics(statistics & st) const {
+        // m_imp->collect_statistics(st);
+    }
+
+    virtual void reset_statistics() {
+        // m_imp->reset_statistics();
+    }
+
+    
+    virtual void cleanup() {
+        ast_manager & m = m_imp->m;
+        imp * d = m_imp;
+        #pragma omp critical (tactic_cancel)
+        {
+            m_imp = 0;
+        }
+        dealloc(d);
+        d = alloc(imp, m, m_params);
+        #pragma omp critical (tactic_cancel)
+        {
+            m_imp = d;
+        }
+    }
+    
+};
+
+tactic * mk_qe_lite_tactic(ast_manager & m, params_ref const & p) {
+    return alloc(qe_lite_tactic, m, p);
+}
+
+template class rewriter_tpl<qe_lite::impl::elim_cfg>;
diff --git a/src/muz_qe/qe_lite.h b/src/muz_qe/qe_lite.h
index 3ffbf8fad..7d9239fa7 100644
--- a/src/muz_qe/qe_lite.h
+++ b/src/muz_qe/qe_lite.h
@@ -23,6 +23,9 @@ Revision History:
 
 #include "ast.h"
 #include "uint_set.h"
+#include "params.h"
+
+class tactic;
 
 class qe_lite {
     class impl;
@@ -56,6 +59,13 @@ public:
         \brief full rewriting based light-weight quantifier elimination round.
     */
     void operator()(expr_ref& fml, proof_ref& pr);
+
+    void set_cancel(bool f);
 };
 
+tactic * mk_qe_lite_tactic(ast_manager & m, params_ref const & p = params_ref());
+/*
+  ADD_TACTIC("qe-light", "apply light-weight quantifier elimination.", "mk_qe_lite_tactic(m, p)")
+*/
+
 #endif 
diff --git a/src/nlsat/nlsat_explain.cpp b/src/nlsat/nlsat_explain.cpp
index ca58b15af..460e07f58 100644
--- a/src/nlsat/nlsat_explain.cpp
+++ b/src/nlsat/nlsat_explain.cpp
@@ -981,6 +981,14 @@ namespace nlsat {
                         bool atom_val = a->get_kind() == atom::EQ;
                         bool lit_val  = l.sign() ? !atom_val : atom_val;
                         new_lit = lit_val ? true_literal : false_literal;
+                        if (!info.m_lc_const) {
+                            // We have essentially shown the current factor must be zero If the leading coefficient is not zero.
+                            // Note that, if the current factor is zero, then the whole polynomial is zero.
+                            // The atom is true if it is an equality, and false otherwise.
+                            // The sign of the leading coefficient (info.m_lc) of info.m_eq doesn't matter.
+                            // However, we have to store the fact it is not zero.
+                            info.add_lc_diseq();
+                        }
                         return;
                     }
                     else if (s == -1 && !is_even) {
@@ -1341,3 +1349,32 @@ namespace nlsat {
     }
 
 };
+
+#ifdef Z3DEBUG
+void pp(nlsat::explain::imp & ex, unsigned num, nlsat::literal const * ls) {
+    ex.display(std::cout, num, ls);
+}
+void pp(nlsat::explain::imp & ex, nlsat::scoped_literal_vector & ls) {
+    ex.display(std::cout, ls);
+}
+void pp(nlsat::explain::imp & ex, polynomial_ref const & p) {
+    ex.display(std::cout, p);
+    std::cout << std::endl;
+}
+void pp(nlsat::explain::imp & ex, polynomial::polynomial * p) {
+    polynomial_ref _p(p, ex.m_pm);
+    ex.display(std::cout, _p);
+    std::cout << std::endl;
+}
+void pp(nlsat::explain::imp & ex, polynomial_ref_vector const & ps) {
+    ex.display(std::cout, ps);
+}
+void pp_var(nlsat::explain::imp & ex, nlsat::var x) {
+    ex.display(std::cout, x);
+    std::cout << std::endl;
+}
+void pp_lit(nlsat::explain::imp & ex, nlsat::literal l) {
+    ex.display(std::cout, l);
+    std::cout << std::endl;
+}
+#endif
diff --git a/src/nlsat/nlsat_explain.h b/src/nlsat/nlsat_explain.h
index 08f6201be..5ecb9d385 100644
--- a/src/nlsat/nlsat_explain.h
+++ b/src/nlsat/nlsat_explain.h
@@ -27,7 +27,9 @@ namespace nlsat {
     class evaluator;
     
     class explain {
+    public:
         struct imp;
+    private:
         imp * m_imp;
     public:
         explain(solver & s, assignment const & x2v, polynomial::cache & u, atom_vector const & atoms, atom_vector const & x2eq,
diff --git a/src/parsers/smt/smtlib_solver.cpp b/src/parsers/smt/smtlib_solver.cpp
index ef28216bf..7c8572ad8 100644
--- a/src/parsers/smt/smtlib_solver.cpp
+++ b/src/parsers/smt/smtlib_solver.cpp
@@ -86,7 +86,7 @@ namespace smtlib {
             benchmark.add_formula(m_ast_manager.mk_true());
         }
         m_ctx = alloc(cmd_context, true, &m_ast_manager, benchmark.get_logic());
-        m_ctx->set_solver(mk_smt_strategic_solver(false));
+        m_ctx->set_solver_factory(mk_smt_strategic_solver_factory());
         theory::expr_iterator fit  = benchmark.begin_formulas();
         theory::expr_iterator fend = benchmark.end_formulas();
         for (; fit != fend; ++fit)
diff --git a/src/parsers/smt/smtparser.cpp b/src/parsers/smt/smtparser.cpp
index d3b2feeb7..c1ebd251b 100644
--- a/src/parsers/smt/smtparser.cpp
+++ b/src/parsers/smt/smtparser.cpp
@@ -483,13 +483,13 @@ public:
 class array_sort : public builtin_sort_builder {
 public:
     array_sort(ast_manager& m) : 
-        builtin_sort_builder(m, m.get_family_id("array"), ARRAY_SORT) {}
+        builtin_sort_builder(m, m.mk_family_id("array"), ARRAY_SORT) {}
 };
 
 class bv_sort : public builtin_sort_builder {
 public:
     bv_sort(ast_manager& m) : 
-        builtin_sort_builder(m, m.get_family_id("bv"), BV_SORT) {}
+        builtin_sort_builder(m, m.mk_family_id("bv"), BV_SORT) {}
 };
 
 class user_sort : public sort_builder {    
@@ -538,7 +538,7 @@ class smtparser : public parser {
     public:
         add_plugins(ast_manager& m) {
 #define REGISTER_PLUGIN(NAME, MK) {                             \
-                family_id fid = m.get_family_id(symbol(NAME));  \
+                family_id fid = m.mk_family_id(symbol(NAME));  \
                 if (!m.has_plugin(fid)) {                       \
                     m.register_plugin(fid, MK);                 \
                 }                                                       \
@@ -681,7 +681,7 @@ public:
         smtlib::symtable* table = m_benchmark.get_symtable();
 
         symbol arith("arith");
-        family_id afid = m_manager.get_family_id(arith);
+        family_id afid = m_manager.mk_family_id(arith);
         m_arith_fid = afid;
 
         add_builtin_type("Int", afid, INT_SORT);
@@ -694,7 +694,7 @@ public:
         add_builtins(afid);
         
         symbol bv("bv");
-        family_id bfid = m_manager.get_family_id(bv);
+        family_id bfid = m_manager.mk_family_id(bv);
         m_bv_fid = bfid;        
 
         add_builtins(bfid);
@@ -702,7 +702,7 @@ public:
         add_builtin_type("BitVec", bfid, BV_SORT);
 
         symbol array("array");
-        afid = m_manager.get_family_id(array);
+        afid = m_manager.mk_family_id(array);
         m_array_fid = afid;
 
         add_builtins(afid);
diff --git a/src/parsers/smt2/smt2parser.cpp b/src/parsers/smt2/smt2parser.cpp
index c99c362bd..0698f4eaf 100644
--- a/src/parsers/smt2/smt2parser.cpp
+++ b/src/parsers/smt2/smt2parser.cpp
@@ -390,6 +390,7 @@ namespace smt2 {
         void check_float(char const * msg) { if (!curr_is_float()) throw parser_exception(msg); }
 
         void error(unsigned line, unsigned pos, char const * msg) {
+            m_ctx.reset_cancel();
             if (use_vs_format()) {
                 m_ctx.diagnostic_stream() << "Z3(" << line << ", " << pos << "): ERROR: " << msg;
                 if (msg[strlen(msg)-1] != '\n')
diff --git a/src/parsers/util/pattern_validation.h b/src/parsers/util/pattern_validation.h
index d78502a8f..99024097e 100644
--- a/src/parsers/util/pattern_validation.h
+++ b/src/parsers/util/pattern_validation.h
@@ -32,11 +32,10 @@ class pattern_validator {
 public:
     pattern_validator(ast_manager const & m):
         m_bfid(m.get_basic_family_id()),
-        m_lfid(m.get_family_id("label")) {
+        m_lfid(m.get_label_family_id()) {
     }
 
     bool operator()(unsigned num_bindings, unsigned num_new_bindings, expr * n);
-
     bool operator()(unsigned num_new_bindings, expr * n) { return operator()(UINT_MAX, num_new_bindings, n); }
 };
 
diff --git a/src/shell/smtlib_frontend.cpp b/src/shell/smtlib_frontend.cpp
index 1551329c6..ef0b4ad6b 100644
--- a/src/shell/smtlib_frontend.cpp
+++ b/src/shell/smtlib_frontend.cpp
@@ -30,9 +30,6 @@ Revision History:
 #include"subpaving_cmds.h"
 #include"smt_strategic_solver.h"
 
-#include"tactic2solver.h"
-#include"qfnra_nlsat_tactic.h"
-
 extern bool g_display_statistics;
 extern void display_config();
 static clock_t             g_start_time;
@@ -98,8 +95,7 @@ unsigned read_smtlib2_commands(char const * file_name) {
     signal(SIGINT, on_ctrl_c);
     cmd_context ctx;
 
-    solver * s = mk_smt_strategic_solver(false);
-    ctx.set_solver(s);
+    ctx.set_solver_factory(mk_smt_strategic_solver_factory());
 
     install_dl_cmds(ctx);
     install_dbg_cmds(ctx);
diff --git a/src/smt/asserted_formulas.cpp b/src/smt/asserted_formulas.cpp
index 6da2c15f5..3155d9c58 100644
--- a/src/smt/asserted_formulas.cpp
+++ b/src/smt/asserted_formulas.cpp
@@ -189,7 +189,7 @@ void asserted_formulas::push_scope() {
     s.m_asserted_formulas_lim    = m_asserted_formulas.size();
     SASSERT(inconsistent() || s.m_asserted_formulas_lim == m_asserted_qhead);
     s.m_inconsistent_old         = m_inconsistent;
-    m_defined_names.push_scope();
+    m_defined_names.push();
     m_bv_sharing.push_scope();
     commit();
 }
@@ -201,7 +201,7 @@ void asserted_formulas::pop_scope(unsigned num_scopes) {
     unsigned new_lvl    = m_scopes.size() - num_scopes;
     scope & s           = m_scopes[new_lvl];
     m_inconsistent      = s.m_inconsistent_old;
-    m_defined_names.pop_scope(num_scopes);
+    m_defined_names.pop(num_scopes);
     m_asserted_formulas.shrink(s.m_asserted_formulas_lim);
     if (m_manager.proofs_enabled())
         m_asserted_formula_prs.shrink(s.m_asserted_formulas_lim);
@@ -439,6 +439,8 @@ void asserted_formulas::nnf_cnf() {
         expr_ref   r1(m_manager);
         proof_ref  pr1(m_manager);
         CASSERT("well_sorted",is_well_sorted(m_manager, n));
+        push_todo.reset();
+        push_todo_prs.reset();
         apply_nnf(n, push_todo, push_todo_prs, r1, pr1);
         CASSERT("well_sorted",is_well_sorted(m_manager, r1));
         pr = m_manager.mk_modus_ponens(pr, pr1);
@@ -855,3 +857,8 @@ void asserted_formulas::max_bv_sharing() {
     
 }
 
+#ifdef Z3DEBUG
+void pp(asserted_formulas & f) {
+    f.display(std::cout);
+}
+#endif
diff --git a/src/smt/params/qi_params.h b/src/smt/params/qi_params.h
index b0a21e75b..0cd817f22 100644
--- a/src/smt/params/qi_params.h
+++ b/src/smt/params/qi_params.h
@@ -52,8 +52,6 @@ struct qi_params {
     bool               m_mbqi_trace;
     unsigned           m_mbqi_force_template;
 
-    bool               m_instgen;
-
     qi_params(params_ref const & p = params_ref()):
         /*
           The "weight 0" performance bug
@@ -99,8 +97,7 @@ struct qi_params {
         m_mbqi_max_cexs_incr(1),
         m_mbqi_max_iterations(1000),
         m_mbqi_trace(false),
-        m_mbqi_force_template(10),
-        m_instgen(false) {
+        m_mbqi_force_template(10) {
         updt_params(p);
     }
 
diff --git a/src/smt/params/smt_params.cpp b/src/smt/params/smt_params.cpp
index ec2fbc93c..519302c19 100644
--- a/src/smt/params/smt_params.cpp
+++ b/src/smt/params/smt_params.cpp
@@ -18,6 +18,7 @@ Revision History:
 --*/
 #include"smt_params.h"
 #include"smt_params_helper.hpp"
+#include"model_params.hpp"
 
 void smt_params::updt_local_params(params_ref const & _p) {
     smt_params_helper p(_p);
@@ -33,6 +34,8 @@ void smt_params::updt_local_params(params_ref const & _p) {
     m_delay_units_threshold = p.delay_units_threshold();
     m_preprocess = _p.get_bool("preprocess", true); // hidden parameter
     m_soft_timeout = p.soft_timeout();
+    model_params mp(_p);
+    m_model_compact = mp.compact();
     if (_p.get_bool("arith.greatest_error_pivot", false))
         m_arith_pivot_strategy = ARITH_PIVOT_GREATEST_ERROR;
     else if (_p.get_bool("arith.least_error_pivot", false))
@@ -50,6 +53,4 @@ void smt_params::updt_params(params_ref const & p) {
 void smt_params::updt_params(context_params const & p) {
     m_auto_config    = p.m_auto_config;
     m_model          = p.m_model;
-    m_model_validate = p.m_model_validate;
 }
-
diff --git a/src/smt/params/smt_params.h b/src/smt/params/smt_params.h
index 3d823cb51..256c5a646 100644
--- a/src/smt/params/smt_params.h
+++ b/src/smt/params/smt_params.h
@@ -177,7 +177,6 @@ struct smt_params : public preprocessor_params,
     // -----------------------------------
     bool             m_model; 
     bool             m_model_compact;
-    bool             m_model_validate;
     bool             m_model_on_timeout;
     bool             m_model_on_final_check;
 
@@ -264,7 +263,6 @@ struct smt_params : public preprocessor_params,
         m_abort_after_preproc(false),
         m_model(true),
         m_model_compact(false),
-        m_model_validate(false),
         m_model_on_timeout(false),
         m_model_on_final_check(false),
         m_progress_sampling_freq(0),
diff --git a/src/smt/proto_model/array_factory.cpp b/src/smt/proto_model/array_factory.cpp
index b91857e40..a929f6d9a 100644
--- a/src/smt/proto_model/array_factory.cpp
+++ b/src/smt/proto_model/array_factory.cpp
@@ -34,7 +34,7 @@ func_decl * mk_aux_decl_for_array_sort(ast_manager & m, sort * s) {
 }
 
 array_factory::array_factory(ast_manager & m, proto_model & md):
-    struct_factory(m, m.get_family_id("array"), md) {
+    struct_factory(m, m.mk_family_id("array"), md) {
 }
 
 /**
diff --git a/src/smt/proto_model/datatype_factory.cpp b/src/smt/proto_model/datatype_factory.cpp
index 0ea610869..5be802714 100644
--- a/src/smt/proto_model/datatype_factory.cpp
+++ b/src/smt/proto_model/datatype_factory.cpp
@@ -22,7 +22,7 @@ Revision History:
 #include"ast_ll_pp.h"
 
 datatype_factory::datatype_factory(ast_manager & m, proto_model & md):
-    struct_factory(m, m.get_family_id("datatype"), md),
+    struct_factory(m, m.mk_family_id("datatype"), md),
     m_util(m) {
 }
 
diff --git a/src/smt/proto_model/numeral_factory.cpp b/src/smt/proto_model/numeral_factory.cpp
index 9653322e3..a67b6c075 100644
--- a/src/smt/proto_model/numeral_factory.cpp
+++ b/src/smt/proto_model/numeral_factory.cpp
@@ -24,7 +24,7 @@ app * arith_factory::mk_value_core(rational const & val, sort * s) {
 }
 
 arith_factory::arith_factory(ast_manager & m):
-    numeral_factory(m, m.get_family_id("arith")),
+    numeral_factory(m, m.mk_family_id("arith")),
     m_util(m) {
 }
 
@@ -36,7 +36,7 @@ app * arith_factory::mk_value(rational const & val, bool is_int) {
 }
 
 bv_factory::bv_factory(ast_manager & m):
-    numeral_factory(m, m.get_family_id("bv")),
+    numeral_factory(m, m.mk_family_id("bv")),
     m_util(m) {
 }
 
diff --git a/src/smt/proto_model/proto_model.cpp b/src/smt/proto_model/proto_model.cpp
index 92110bc1a..d7a06f14f 100644
--- a/src/smt/proto_model/proto_model.cpp
+++ b/src/smt/proto_model/proto_model.cpp
@@ -31,7 +31,7 @@ proto_model::proto_model(ast_manager & m, simplifier & s, params_ref const & p):
     model_core(m),
     m_asts(m),
     m_simplifier(s),
-    m_afid(m.get_family_id(symbol("array"))) {
+    m_afid(m.mk_family_id(symbol("array"))) {
     register_factory(alloc(basic_factory, m));
     m_user_sort_factory = alloc(user_sort_factory, m);
     register_factory(m_user_sort_factory);
diff --git a/src/smt/proto_model/value_factory.cpp b/src/smt/proto_model/value_factory.cpp
index 0b2aded9e..93294d898 100644
--- a/src/smt/proto_model/value_factory.cpp
+++ b/src/smt/proto_model/value_factory.cpp
@@ -51,7 +51,7 @@ expr * basic_factory::get_fresh_value(sort * s) {
 }
 
 user_sort_factory::user_sort_factory(ast_manager & m): 
-    simple_factory<unsigned>(m, m.get_family_id("user-sort")) {
+    simple_factory<unsigned>(m, m.mk_family_id("user-sort")) {
 }
 
 void user_sort_factory::freeze_universe(sort * s) {
diff --git a/src/smt/smt_context.cpp b/src/smt/smt_context.cpp
index a7623832f..02ee06985 100644
--- a/src/smt/smt_context.cpp
+++ b/src/smt/smt_context.cpp
@@ -2854,7 +2854,12 @@ namespace smt {
         m_bool_var2assumption.reset();
         m_unsat_core.reset();
         if (num_assumptions > 0) {
-            propagate(); // we must give a chance to the theories to propagate before we create a new scope...
+            // We must give a chance to the theories to propagate before we create a new scope...
+            propagate(); 
+            // Internal backtracking scopes (created with push_scope()) must only be created when we are
+            // in a consistent context.
+            if (inconsistent())
+                return; 
             push_scope();
             for (unsigned i = 0; i < num_assumptions; i++) {
                 expr * curr_assumption = assumptions[i];
@@ -3987,3 +3992,8 @@ namespace smt {
 
 };
 
+#ifdef Z3DEBUG
+void pp(smt::context & c) {
+    c.display(std::cout);
+}
+#endif
diff --git a/src/smt/smt_implied_equalities.cpp b/src/smt/smt_implied_equalities.cpp
index c6f28d4b2..70229ccab 100644
--- a/src/smt/smt_implied_equalities.cpp
+++ b/src/smt/smt_implied_equalities.cpp
@@ -21,23 +21,21 @@ Revision History:
 
 #include "smt_implied_equalities.h"
 #include "union_find.h"
-#include "cmd_context.h"
-#include "parametric_cmd.h"
 #include "ast_pp.h"
-#include "arith_decl_plugin.h"
-#include "datatype_decl_plugin.h"
 #include "array_decl_plugin.h"
 #include "uint_set.h"
-#include "model_v2_pp.h"
 #include "smt_value_sort.h"
-
+#include "model_smt2_pp.h"
+#include "stopwatch.h"
+#include "model.h"
+#include "solver.h"
 
 namespace smt {
 
     class get_implied_equalities_impl {
         
         ast_manager&                       m;
-        smt::kernel&                       m_solver;
+        solver&                            m_solver;
         union_find_default_ctx             m_df;
         union_find<union_find_default_ctx> m_uf;
         array_util                         m_array_util;
@@ -98,7 +96,7 @@ namespace smt {
                     ++m_stats_calls;
                     m_solver.push();
                     m_solver.assert_expr(m.mk_not(m.mk_eq(s, t)));
-                    bool is_eq = l_false == m_solver.check();
+                    bool is_eq = l_false == m_solver.check_sat(0,0);
                     m_solver.pop(1);
                     TRACE("get_implied_equalities", tout << mk_pp(t, m) << " = " << mk_pp(s, m) << " " << (is_eq?"eq":"unrelated") << "\n";);
                     if (is_eq) {
@@ -125,7 +123,7 @@ namespace smt {
                     m_stats_timer.start();
                     m_solver.push();
                     m_solver.assert_expr(m.mk_not(m.mk_eq(s, t)));
-                    bool is_eq = l_false == m_solver.check();
+                    bool is_eq = l_false == m_solver.check_sat(0,0);
                     m_solver.pop(1);
                     m_stats_timer.stop();
                     TRACE("get_implied_equalities", tout << mk_pp(t, m) << " = " << mk_pp(s, m) << " " << (is_eq?"eq":"unrelated") << "\n";);
@@ -168,7 +166,7 @@ namespace smt {
                     terms[i].term = m.mk_app(m_array_util.get_family_id(), OP_SELECT, 0, 0, args.size(), args.c_ptr());
                 }
                 assert_relevant(terms);
-                lbool is_sat = m_solver.check();
+                lbool is_sat = m_solver.check_sat(0,0);
                 model_ref model1;
                 m_solver.get_model(model1);
                 SASSERT(model1.get());
@@ -218,7 +216,7 @@ namespace smt {
                     expr* s = terms[vec[j]].term;
                     m_solver.push();
                     m_solver.assert_expr(m.mk_not(m.mk_eq(t, s)));
-                    lbool is_sat = m_solver.check();
+                    lbool is_sat = m_solver.check_sat(0,0);
                     m_solver.pop(1);
                     TRACE("get_implied_equalities", tout << mk_pp(t, m) << " = " << mk_pp(s, m) << " " << is_sat << "\n";);
                     if (is_sat == l_false) {
@@ -237,7 +235,7 @@ namespace smt {
 
 
             if (!non_values.empty()) {
-                TRACE("get_implied_equalities", model_v2_pp(tout, *model, true););
+                TRACE("get_implied_equalities", model_smt2_pp(tout, m, *model, 0););
                 get_implied_equalities_filter_basic(non_values, terms);
                 //get_implied_equalities_basic(terms);
             }
@@ -321,7 +319,7 @@ namespace smt {
 
     public:
         
-        get_implied_equalities_impl(smt::kernel& s) : m(s.m()), m_solver(s), m_uf(m_df), m_array_util(m), m_stats_calls(0) {}
+        get_implied_equalities_impl(ast_manager& m, solver& s) : m(m), m_solver(s), m_uf(m_df), m_array_util(m), m_stats_calls(0) {}
         
         lbool operator()(unsigned num_terms, expr* const* terms, unsigned* class_ids) {
             params_ref p;
@@ -338,7 +336,7 @@ namespace smt {
 
             m_solver.push();
             assert_relevant(num_terms, terms);
-            lbool is_sat = m_solver.check();
+            lbool is_sat = m_solver.check_sat(0,0);
             
             if (is_sat != l_false) {      
                 model_ref model;
@@ -374,8 +372,8 @@ namespace smt {
     stopwatch get_implied_equalities_impl::s_timer;
     stopwatch get_implied_equalities_impl::s_stats_val_eq_timer;
 
-    lbool implied_equalities(smt::kernel& solver, unsigned num_terms, expr* const* terms, unsigned* class_ids) {        
-        get_implied_equalities_impl gi(solver);
+    lbool implied_equalities(ast_manager& m, solver& solver, unsigned num_terms, expr* const* terms, unsigned* class_ids) {        
+        get_implied_equalities_impl gi(m, solver);
         return gi(num_terms, terms, class_ids);
     }
 };
@@ -552,7 +550,7 @@ namespace smt {
                 m_solver.assert_expr(m.mk_implies(eq_lit, eq));
             }
             m_solver.assert_expr(m.mk_not(m.mk_and(eqs.size(), eqs.c_ptr())));
-            lbool is_sat = m_solver.check();
+            lbool is_sat = m_solver.check_sat(0,0);
             switch(is_sat) {
             case l_false:
                 for (unsigned i = 0; i + 1 < terms.size(); ++i) {
diff --git a/src/smt/smt_implied_equalities.h b/src/smt/smt_implied_equalities.h
index 6fc002ff1..ec9b4bd21 100644
--- a/src/smt/smt_implied_equalities.h
+++ b/src/smt/smt_implied_equalities.h
@@ -23,13 +23,16 @@ Revision History:
 #ifndef __SMT_IMPLIED_EQUALITIES_H__
 #define __SMT_IMPLIED_EQUALITIES_H__
 
-#include"smt_kernel.h"
+#include"smt_solver.h"
+#include"lbool.h"
+#include"ast.h"
 
 
 namespace smt {
         
     lbool implied_equalities(
-        kernel & solver,
+        ast_manager & m, 
+        solver & solver,
         unsigned num_terms, expr* const* terms, 
         unsigned* class_ids);            
 
diff --git a/src/smt/smt_internalizer.cpp b/src/smt/smt_internalizer.cpp
index b3f16a3ce..42e761b61 100644
--- a/src/smt/smt_internalizer.cpp
+++ b/src/smt/smt_internalizer.cpp
@@ -23,7 +23,6 @@ Revision History:
 #include"ast_smt2_pp.h"
 #include"smt_model_finder.h"
 #include"for_each_expr.h"
-#include"theory_instgen.h"
 
 namespace smt {
 
@@ -530,11 +529,6 @@ namespace smt {
         SASSERT(!b_internalized(q));
         SASSERT(q->is_forall());
         SASSERT(check_patterns(q));
-        if (m_fparams.m_instgen) {
-            theory* th = m_theories.get_plugin(m_manager.get_family_id("inst_gen"));
-            static_cast<theory_instgen*>(th)->internalize_quantifier(q);
-            return;
-        }
         bool_var v             = mk_bool_var(q);
         unsigned generation    = m_generation;
         unsigned _generation;
diff --git a/src/smt/smt_kernel.cpp b/src/smt/smt_kernel.cpp
index 779c68625..8ecd079bf 100644
--- a/src/smt/smt_kernel.cpp
+++ b/src/smt/smt_kernel.cpp
@@ -253,12 +253,10 @@ namespace smt {
     }
 
     lbool kernel::setup_and_check() {
-        set_cancel(false);
         return m_imp->setup_and_check();
     }
 
     lbool kernel::check(unsigned num_assumptions, expr * const * assumptions) {
-        set_cancel(false);
         lbool r = m_imp->check(num_assumptions, assumptions);
         TRACE("smt_kernel", tout << "check result: " << r << "\n";);
         return r;
diff --git a/src/smt/smt_model_finder.cpp b/src/smt/smt_model_finder.cpp
index 619a7d60c..e69b7a1b6 100644
--- a/src/smt/smt_model_finder.cpp
+++ b/src/smt/smt_model_finder.cpp
@@ -454,8 +454,8 @@ namespace smt {
                 m_model(0),
                 m_eval_cache_range(m),
                 m_new_constraints(0) {
-                m_asimp  = static_cast<arith_simplifier_plugin*>(s.get_plugin(m.get_family_id("arith")));
-                m_bvsimp = static_cast<bv_simplifier_plugin*>(s.get_plugin(m.get_family_id("bv")));
+                m_asimp  = static_cast<arith_simplifier_plugin*>(s.get_plugin(m.mk_family_id("arith")));
+                m_bvsimp = static_cast<bv_simplifier_plugin*>(s.get_plugin(m.mk_family_id("bv")));
             }
 
             ~auf_solver() {
diff --git a/src/smt/smt_model_finder.h b/src/smt/smt_model_finder.h
index 20d9ba6ef..b89603912 100644
--- a/src/smt/smt_model_finder.h
+++ b/src/smt/smt_model_finder.h
@@ -33,7 +33,7 @@ Abstract:
       Lugano, Switzerland, 2010.
 
     - Bugs, Moles and Skeletons: Symbolic Reasoning for Software
-      Development, Leonardo de Moura, Nikolaj Bjørner, IJCAR,
+      Development, Leonardo de Moura, Nikolaj Bjorner, IJCAR,
       Edinburgh, Scotland, 2010.
 
 Author:
diff --git a/src/smt/smt_setup.cpp b/src/smt/smt_setup.cpp
index ac31eb1a9..96673e67e 100644
--- a/src/smt/smt_setup.cpp
+++ b/src/smt/smt_setup.cpp
@@ -28,7 +28,6 @@ Revision History:
 #include"theory_datatype.h"
 #include"theory_dummy.h"
 #include"theory_dl.h"
-#include"theory_instgen.h"
 #include"theory_seq_empty.h"
 
 namespace smt {
@@ -693,7 +692,7 @@ namespace smt {
     void setup::setup_arith() {
         switch(m_params.m_arith_mode) {
         case AS_NO_ARITH:
-            m_context.register_plugin(alloc(smt::theory_dummy, m_manager.get_family_id("arith"), "no arithmetic"));
+            m_context.register_plugin(alloc(smt::theory_dummy, m_manager.mk_family_id("arith"), "no arithmetic"));
             break;
         case AS_DIFF_LOGIC:
             if (m_params.m_arith_fixnum) {
@@ -735,7 +734,7 @@ namespace smt {
     void setup::setup_bv() {
         switch(m_params.m_bv_mode) {
         case BS_NO_BV:
-            m_context.register_plugin(alloc(smt::theory_dummy, m_manager.get_family_id("bv"), "no bit-vector"));
+            m_context.register_plugin(alloc(smt::theory_dummy, m_manager.mk_family_id("bv"), "no bit-vector"));
             break;
         case BS_BLASTER:
             m_context.register_plugin(alloc(smt::theory_bv, m_manager, m_params, m_params));
@@ -746,7 +745,7 @@ namespace smt {
     void setup::setup_arrays() {
         switch(m_params.m_array_mode) {
         case AR_NO_ARRAY:
-            m_context.register_plugin(alloc(smt::theory_dummy, m_manager.get_family_id("array"), "no array"));
+            m_context.register_plugin(alloc(smt::theory_dummy, m_manager.mk_family_id("array"), "no array"));
             break;
         case AR_SIMPLE:
             m_context.register_plugin(alloc(smt::theory_array, m_manager, m_params));
@@ -772,11 +771,6 @@ namespace smt {
     void setup::setup_seq() {
         m_context.register_plugin(alloc(theory_seq_empty, m_manager));
     }
-    void setup::setup_instgen() {
-        if (m_params.m_instgen) {
-            m_context.register_plugin(mk_theory_instgen(m_manager, m_params));
-        }
-    }
 
     void setup::setup_unknown() {
         setup_arith();
@@ -784,7 +778,6 @@ namespace smt {
         setup_bv();
         setup_datatypes();
         setup_dl();
-        setup_instgen();
         setup_seq();
     }
 
diff --git a/src/smt/smt_solver.cpp b/src/smt/smt_solver.cpp
index e8c1c6698..1fbb58847 100644
--- a/src/smt/smt_solver.cpp
+++ b/src/smt/smt_solver.cpp
@@ -25,166 +25,114 @@ namespace smt {
 
     class solver : public solver_na2as {
         smt_params          m_params;
-        smt::kernel *       m_context;
+        smt::kernel         m_context;
         progress_callback * m_callback;
+        symbol              m_logic;
     public:
-        solver():m_context(0), m_callback(0) {}
-
+        solver(ast_manager & m, params_ref const & p, symbol const & l):
+            solver_na2as(m),
+            m_params(p),
+            m_context(m, m_params) {
+            m_logic = l;
+            if (m_logic != symbol::null)
+                m_context.set_logic(m_logic);
+        }
+        
         virtual ~solver() {
-            if (m_context != 0)
-                dealloc(m_context);
         }
 
         virtual void updt_params(params_ref const & p) {
             m_params.updt_params(p);
-            if (m_context == 0)
-                return;
-            m_context->updt_params(p);
+            m_context.updt_params(p);
         }
 
         virtual void collect_param_descrs(param_descrs & r) {
-            if (m_context == 0) {
-                ast_manager m;
-                reg_decl_plugins(m);
-                smt::kernel s(m, m_params);
-                s.collect_param_descrs(r);
-            }
-            else {
-                m_context->collect_param_descrs(r);
-            }
-        }
-
-        virtual void init_core(ast_manager & m, symbol const & logic) {
-            reset();
-            // We can throw exceptions when creating a smt::kernel object
-            // So, we should create the smt::kernel outside of the criticial section
-            // block. OMP does not allow exceptions to cross critical section boundaries.
-            smt::kernel * new_kernel = alloc(smt::kernel, m, m_params);
-            #pragma omp critical (solver)
-            {
-                m_context = new_kernel;
-                if (m_callback)
-                    m_context->set_progress_callback(m_callback);
-            }
-            if (logic != symbol::null)
-                m_context->set_logic(logic);
+            m_context.collect_param_descrs(r);
         }
 
         virtual void collect_statistics(statistics & st) const {
-            if (m_context == 0) {
-                return;
-            }
-            else {
-                m_context->collect_statistics(st);
-            }
-        }
-
-        virtual void reset_core() {
-            if (m_context != 0) {
-                #pragma omp critical (solver)
-                {
-                    dealloc(m_context);
-                    m_context = 0;
-                }
-            }
-        }
-        
-        // An exception may be thrown when creating a smt::kernel.
-        // So, there is no guarantee that m_context != 0 when
-        // using smt_solver from the SMT 2.0 command line frontend.
-        void check_context() const {
-            if (m_context == 0)
-                throw default_exception("Z3 failed to create solver, check previous error messages");
+            m_context.collect_statistics(st);
         }
 
         virtual void assert_expr(expr * t) {
-            check_context();
-            m_context->assert_expr(t);
+            m_context.assert_expr(t);
         }
 
         virtual void push_core() {
-            check_context();
-            m_context->push();
+            m_context.push();
         }
 
         virtual void pop_core(unsigned n) {
-            check_context();
-            m_context->pop(n);
+            m_context.pop(n);
         }
 
         virtual lbool check_sat_core(unsigned num_assumptions, expr * const * assumptions) {
-            check_context();
             TRACE("solver_na2as", tout << "smt_solver::check_sat_core: " << num_assumptions << "\n";);
-            return m_context->check(num_assumptions, assumptions);
+            return m_context.check(num_assumptions, assumptions);
         }
 
         virtual void get_unsat_core(ptr_vector<expr> & r) {
-            check_context();
-            unsigned sz = m_context->get_unsat_core_size();
+            unsigned sz = m_context.get_unsat_core_size();
             for (unsigned i = 0; i < sz; i++)
-                r.push_back(m_context->get_unsat_core_expr(i));
+                r.push_back(m_context.get_unsat_core_expr(i));
         }
 
         virtual void get_model(model_ref & m) {
-            check_context();
-            m_context->get_model(m);
+            m_context.get_model(m);
         }
 
         virtual proof * get_proof() {
-            check_context();
-            return m_context->get_proof();
+            return m_context.get_proof();
         }
 
         virtual std::string reason_unknown() const {
-            check_context();
-            return m_context->last_failure_as_string();
+            return m_context.last_failure_as_string();
         }
 
         virtual void get_labels(svector<symbol> & r) {
-            check_context();
             buffer<symbol> tmp;
-            m_context->get_relevant_labels(0, tmp);
+            m_context.get_relevant_labels(0, tmp);
             r.append(tmp.size(), tmp.c_ptr());
         }
 
         virtual void set_cancel(bool f) {
-#pragma omp critical (solver)
-            {
-                if (m_context) 
-                    m_context->set_cancel(f);
-            }
+            m_context.set_cancel(f);
         }
 
         virtual void set_progress_callback(progress_callback * callback) {
             m_callback = callback;
-            if (m_context)
-                m_context->set_progress_callback(callback);
+            m_context.set_progress_callback(callback);
         }
 
         virtual unsigned get_num_assertions() const {
-            if (m_context)
-                return m_context->size();
-            else
-                return 0;
+            return m_context.size();
         }
     
         virtual expr * get_assertion(unsigned idx) const {
-            SASSERT(m_context);
             SASSERT(idx < get_num_assertions());
-            return m_context->get_formulas()[idx];
+            return m_context.get_formulas()[idx];
         }
 
         virtual void display(std::ostream & out) const {
-            if (m_context)
-                m_context->display(out);
-            else
-                out << "(solver)";
+            m_context.display(out);
         }
    
     };
 
 };
 
-solver * mk_smt_solver() {
-    return alloc(smt::solver);
+solver * mk_smt_solver(ast_manager & m, params_ref const & p, symbol const & logic) {
+    return alloc(smt::solver, m, p, logic);
 }
+
+class smt_solver_factory : public solver_factory {
+public:
+    virtual solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) {
+        return mk_smt_solver(m, p, logic);
+    }
+};
+
+solver_factory * mk_smt_solver_factory() {
+    return alloc(smt_solver_factory);
+}
+
diff --git a/src/smt/smt_solver.h b/src/smt/smt_solver.h
index e9af9aafa..81c9a1319 100644
--- a/src/smt/smt_solver.h
+++ b/src/smt/smt_solver.h
@@ -21,8 +21,13 @@ Notes:
 #ifndef _SMT_SOLVER_H_
 #define _SMT_SOLVER_H_
 
-class solver;
+#include"ast.h"
+#include"params.h"
 
-solver * mk_smt_solver();
+class solver;
+class solver_factory;
+
+solver * mk_smt_solver(ast_manager & m, params_ref const & p, symbol const & logic);
+solver_factory * mk_smt_solver_factory();
 
 #endif
diff --git a/src/smt/theory_arith_core.h b/src/smt/theory_arith_core.h
index b774fb3d9..fafe73a79 100644
--- a/src/smt/theory_arith_core.h
+++ b/src/smt/theory_arith_core.h
@@ -1294,7 +1294,7 @@ namespace smt {
     
     template<typename Ext>
     theory_arith<Ext>::theory_arith(ast_manager & m, theory_arith_params & params):
-        theory(m.get_family_id("arith")),
+        theory(m.mk_family_id("arith")),
         m_params(params),
         m_util(m),
         m_arith_eq_solver(m),
diff --git a/src/smt/theory_array_base.cpp b/src/smt/theory_array_base.cpp
index ca6449d1d..c2c50567f 100644
--- a/src/smt/theory_array_base.cpp
+++ b/src/smt/theory_array_base.cpp
@@ -27,7 +27,7 @@ Revision History:
 namespace smt {
 
     theory_array_base::theory_array_base(ast_manager & m):
-        theory(m.get_family_id("array")),
+        theory(m.mk_family_id("array")),
         m_found_unsupported_op(false)
     {
     }
diff --git a/src/smt/theory_bv.cpp b/src/smt/theory_bv.cpp
index e425071d2..559ce155b 100644
--- a/src/smt/theory_bv.cpp
+++ b/src/smt/theory_bv.cpp
@@ -1239,7 +1239,7 @@ namespace smt {
     }
 
     theory_bv::theory_bv(ast_manager & m, theory_bv_params const & params, bit_blaster_params const & bb_params):
-        theory(m.get_family_id("bv")),
+        theory(m.mk_family_id("bv")),
         m_params(params),
         m_util(m),
         m_autil(m),
diff --git a/src/smt/theory_datatype.cpp b/src/smt/theory_datatype.cpp
index 65abfe238..8c6543eff 100644
--- a/src/smt/theory_datatype.cpp
+++ b/src/smt/theory_datatype.cpp
@@ -454,7 +454,7 @@ namespace smt {
     }
 
     theory_datatype::theory_datatype(ast_manager & m, theory_datatype_params & p):
-        theory(m.get_family_id("datatype")),
+        theory(m.mk_family_id("datatype")),
         m_params(p),
         m_util(m),
         m_find(*this),
diff --git a/src/smt/theory_dense_diff_logic_def.h b/src/smt/theory_dense_diff_logic_def.h
index 4d50bd8bf..21f1262ac 100644
--- a/src/smt/theory_dense_diff_logic_def.h
+++ b/src/smt/theory_dense_diff_logic_def.h
@@ -28,7 +28,7 @@ namespace smt {
 
     template<typename Ext>
     theory_dense_diff_logic<Ext>::theory_dense_diff_logic(ast_manager & m, theory_arith_params & p):
-        theory(m.get_family_id("arith")),
+        theory(m.mk_family_id("arith")),
         m_params(p),
         m_autil(m),
         m_arith_eq_adapter(*this, p, m_autil),
diff --git a/src/smt/theory_diff_logic.h b/src/smt/theory_diff_logic.h
index 264ab9b2d..4140f683c 100644
--- a/src/smt/theory_diff_logic.h
+++ b/src/smt/theory_diff_logic.h
@@ -306,7 +306,7 @@ namespace smt {
 
     public:    
         theory_diff_logic(ast_manager& m, smt_params & params):
-            theory(m.get_family_id("arith")),
+            theory(m.mk_family_id("arith")),
             m_params(params),
             m_util(m),
             m_arith_eq_adapter(*this, params, m_util),
diff --git a/src/smt/theory_dl.cpp b/src/smt/theory_dl.cpp
index 402ab856c..758f78c2c 100644
--- a/src/smt/theory_dl.cpp
+++ b/src/smt/theory_dl.cpp
@@ -88,7 +88,7 @@ namespace smt {
                 m_th.get_rep(s, r, v);
                 app_ref rep_of(m_th.m());
                 rep_of = m_th.m().mk_app(r, m_node->get_owner());
-                theory_id bv_id = m_th.m().get_family_id("bv");
+                theory_id bv_id = m_th.m().mk_family_id("bv");
                 theory_bv* th_bv = dynamic_cast<theory_bv*>(ctx.get_theory(bv_id));
                 SASSERT(th_bv);
                 rational val;
@@ -106,7 +106,7 @@ namespace smt {
         
     public:
         theory_dl(ast_manager& m):
-            theory(m.get_family_id("datalog_relation")),
+            theory(m.mk_family_id("datalog_relation")),
             m_util(m),
             m_bv(m),
             m_trail(m)
diff --git a/src/smt/theory_instgen.cpp b/src/smt/theory_instgen.cpp
deleted file mode 100644
index 68e04aab0..000000000
--- a/src/smt/theory_instgen.cpp
+++ /dev/null
@@ -1,1494 +0,0 @@
-/*++
-Copyright (c) 2011 Microsoft Corporation
-
-Module Name:
-
-    theory_instgen.cpp
-
-Abstract:
-
-    iProver style theory solver.
-    It provides an instantiation based engine
-    based on InstGen methods together with
-    unit propagation.
-
-Author:
-
-    Krystof Hoder (t-khoder) 
-    Nikolaj Bjorner (nbjorner) 2011-10-6
-
-Revision History:
-
-Main data-structures:
-
-- Instantiation = Var -> Expr
-- MatchingSet = Instantiation-set
-  operations:
-   - has_instance : Instantiation -> Bool
-     has_instance(i) = exists j in MatchingSet . j <= i
-- UnificationIndex 
-  operations:
-   - insert : Expr
-   - remove : Expr
-   - unify : Expr -> Expr-set   
-      - set of inserted expressions that unify
-- RootClauseMap : Expr -> Quantifier
-  where RootClauseMap(clause) = The quantifier that originated clause
-- Occurs : Expr -> Quantifier-set
-  the set of quantifiers where non-ground literal occurs.
-- LiteralMeanings : Literal -> Expr-set 
-  - set of non-ground literals that were grounded to Literal
-- InternalizedFoLits : Expr-set
-  - forall e in InternalizedFoLits . e \in LiteralMeanings(ground(e))
-- MatchingSets : Quantifier -> MatchingSet
-
-
-Main operation:
-
- - insert all assigned literals into UnificationIndex
- - for l' in LiteralMeanings(l) do:       
-       for m',theta in UnificationIndex.unify(not l') do:
-           for q in Occurs(l') do:
-               for q' in Occurs(m') do:
-                   instantiate q  with theta
-                   instantiate q' with theta
-
-    instantiate q with theta:
-        
-Discussion of plans:
-
-- Efficient unit propagation using the tables from dl_
-  See addittional notes under unit propagation.
-  The idea is to perfrm unit propagation using the tables 
-  provided in the dl_ module. This is similar to unit 
-  propagation from the EPR solver and retains succinctness
-  features, but does not carry over the splitting component.
-  The efficient propagator is aimed at solving ground problems more efficiently,
-  for example
-
-- Reduce set of selected literals when clause already has on selected literal.
-
-- Subsumption module:
-  - simplify clause using already asserted clauses.
-  - check for variants.
-
-- Completeness for EPR with equality:
-  The relevant equality clause for EPR are C \/ x = y and C \/ a = x
-  Destructive E-resolution (DER) removes disequalities.
-  Two approaches:
-  1. Rely on super-position/hyper-resolution of ordinary literals 
-     in the clause.
-  2. Instantiate based on congruence closure.
-     The instantiation based approach takes a clause of the form C \/ x = y, 
-     where all other non-equality literals in C are assigned false by the 
-     current assignment, and (the grounded version U = U' of) x = y is 
-     assigned true. Take the equivalence classes of the type of x and 
-     instantiate x, y using representatives for different equivalence
-     classes. The number of instantiations is potentially quadratic 
-     in the number of terms. One reduction considers symmetries: 
-     instantiate x by a smaller representative than y.
-- Unit propagation:
-     - Why should unit-propagation matter: hunch: similar role as 
-       theory propagation where conflicts are created close to root 
-       of search tree.
-     - Add theory identifiers to literals so that assign_eh is invoked.
-     - Produce explanation objects for unit propagation.
-     - Unit propagation index.
-        - Idea only propagate known literals
-- Exchange unit literals with super position engine for equalities.
-  iProver approach: perform unit super-position proof, get instances 
-    by labeling equalities by clauses + substitution (set-labeling)
-  portfolio approach: exchange unit literals to super-position 
-    (or hypotheses as suggested in more general setting).
-      
---*/
-
-#include "theory_instgen.h"
-#include "value_factory.h"
-#include "smt_model_generator.h"
-#include "smt_context.h"
-#include "ast_smt2_pp.h"
-#include "substitution.h"
-#include "substitution_tree.h"
-#include "uint_set.h"
-#include "unifier.h"
-#include "matcher.h"
-#include "rewriter.h"
-#include "rewriter_def.h"
-#include "var_subst.h"
-
-#define PP mk_pp
-
-namespace smt {
-
-
-    //
-    // expression grounding for passing to the SMT solver
-    //
-    class grounder {
-        ast_manager& m;
-        vector<obj_map<sort,expr*> > m_defaults;
-        expr_ref_vector              m_ref_holder;
-
-        class grounding_rewriter_cfg;
-
-        void reserve(unsigned idx) {
-            if (m_defaults.size() <= idx) {
-                m_defaults.resize(idx+1);
-            }
-        }
-
-        expr* mk_default(sort* s) {
-            return mk_default(0, s);
-        }
-
-        expr* mk_default(unsigned i, sort* s) {
-            expr* d;
-            reserve(i);
-            if (!m_defaults[i].find(s, d)) {
-                d = m.mk_fresh_const("U",s);
-                m_defaults[i].insert(s, d);
-                m_ref_holder.push_back(d);
-            }
-            return d;    
-        }
-        
-        class grounding_rewriter_cfg : public default_rewriter_cfg {
-            grounder& m_parent;
-            bool      m_collapse;
-        public:
-            grounding_rewriter_cfg(grounder& parent, bool collapse)
-                : m_parent(parent), m_collapse(collapse) {}
-            
-            bool get_subst(expr * s, expr * & t, proof * & t_pr) {
-                SASSERT(is_app(s) || is_var(s));
-                if (is_var(s)) {
-                    var* v = to_var(s);
-                    if (m_collapse) {
-                        t = m_parent.mk_default(v->get_sort());
-                    }
-                    else {
-                        t = m_parent.mk_default(v->get_idx(), v->get_sort());
-                    }
-                }
-                return is_var(s);
-            }
-        };
-
-        void mk(expr * e, app_ref& res, bool collapse) {
-            if(is_ground(e)) {
-                res = to_app(e);
-            }
-            else {
-                while (is_quantifier(e)) {
-                    e = to_quantifier(e)->get_expr();
-                }
-                SASSERT(is_app(e));
-                grounding_rewriter_cfg r_cfg(*this, collapse);
-                rewriter_tpl<grounding_rewriter_cfg> rwr(m, false, r_cfg);
-                expr_ref res_e(m);
-                rwr(e, res_e);
-                res = to_app(res_e);
-            }
-            SASSERT(is_ground(res.get()));
-        } 
-
-    public:
-        grounder(ast_manager& m): m(m), m_ref_holder(m) {
-            reserve(0);
-        }
-
-        /** 
-            create a grounding that recycles the same constant for
-            different variables of the same sort.
-
-            This function can be called either with whole clauses (incl. quantifier), 
-            or with literals one by one (without a quantifier) 
-        */
-        void operator()(expr * e, app_ref& res) {
-            mk(e, res, true);
-        }
-
-        //
-        // create a grounding where different variables have different names
-        //
-        void mk_diff(expr * e, app_ref& res) {
-            mk(e, res, false);
-        }        
-    };
-
-    //
-    // Class for first-order subsumption checking.
-    // if clause[renaming] is a superset of existing clause in context, then clause is subsumed.
-    // if context => clause         then clause is subsumed.
-    // if context & clause => ~ lit then lit is subsumed from clause
-    //
-    // TBD: 
-    // - check unit propagation
-    // - use internalizer functions directly. The assertions have already been pre-processed.
-    // 
-    class clause_subsumption {
-        ast_manager& m;
-        grounder     m_grounder;
-        smt_params m_params;
-        context      m_ctx;
-        quantifier_ref_vector m_assumptions;
-        unsigned_vector m_limit;
-    public:
-        clause_subsumption(ast_manager& m, smt_params& p): 
-            m(m), m_grounder(m), m_params(p), m_ctx(m,m_params), m_assumptions(m) {
-                m_params.m_instgen = false;
-        }
-        
-        void simplify(quantifier* new_clause, expr_ref& result, ptr_vector<quantifier>& assumptions) {
-#if 1
-            result = new_clause;
-            return;
-#endif 
-
-            SASSERT(new_clause->is_forall());
-            expr* body = new_clause->get_expr();
-            app_ref ground_clause(m);
-            m_grounder.mk_diff(new_clause, ground_clause);
-            if (is_subsumed(ground_clause)) {
-                TRACE("theory_instgen", tout << "subsumed: " << PP(new_clause,m) << "\n";);
-                result = m.mk_true();
-                return;
-            }
-            if (is_homomorphic_image(body)) {
-                result = m.mk_true();
-                return;
-            }
-            // Assert the current clause.
-            m_ctx.internalize(ground_clause, true);
-            m_ctx.assign(m_ctx.get_literal(ground_clause), b_justification());
-            TRACE("theory_instgen", tout << "Asserting: " << PP(ground_clause,m) << "\n";);
-            m_assumptions.push_back(new_clause);
-            SASSERT(m.is_or(body) == m.is_or(ground_clause));
-            if (!m.is_or(body)) {
-                result = new_clause;
-                return;
-            }
-            SASSERT(to_app(body)->get_num_args() == ground_clause->get_num_args());
-            ptr_vector<expr> lits;
-            for (unsigned i = 0; i < to_app(body)->get_num_args(); ++i) {
-                m_ctx.push();
-                m_ctx.assign(m_ctx.get_literal(ground_clause->get_arg(i)), b_justification());
-                lbool is_sat = m_ctx.check();
-                m_ctx.pop(1);
-                if (is_sat != l_false) {
-                    lits.push_back(to_app(body)->get_arg(i));
-                }
-                else {
-                    TRACE("theory_instgen", tout << "subsumed literal: " << PP(to_app(body)->get_arg(i),m) << "\n";);
-                }
-            }
-            if (lits.size() == ground_clause->get_num_args()) {
-                result = new_clause;
-            }
-            else {
-                SASSERT(!lits.empty());
-                result = lits.size()==1?lits[0]:m.mk_or(lits.size(), lits.c_ptr());
-                result = m.update_quantifier(new_clause, result);
-                TRACE("theory_instgen", tout << "simplified: " << PP(new_clause,m) << "\n";
-                                        tout << PP(result.get(), m) << "\n";
-                     );
-                //overapproximation of required assumptions
-                //( m_assumptions.size()-1 ... the -1 is not to make ourselves as an assumption)
-                assumptions.append(m_assumptions.size()-1, m_assumptions.c_ptr());
-            }
-        }
-
-        void push() {
-            m_ctx.push();
-            m_limit.push_back(m_assumptions.size());
-        }
-
-        void pop(unsigned num_scopes) { 
-            m_ctx.pop(num_scopes);
-
-            unsigned last_idx = m_limit.size()-num_scopes;
-            unsigned restored_assumptions_size = m_limit[last_idx];
-            m_limit.resize(last_idx);
-            m_assumptions.resize(restored_assumptions_size);
-        }
-
-    private:
-
-        bool is_subsumed(expr* ground_clause) {
-            m_ctx.push();
-            m_ctx.internalize(ground_clause, true);
-            m_ctx.assign(~m_ctx.get_literal(ground_clause), b_justification());
-            lbool is_sat = m_ctx.check();
-            m_ctx.pop(1);
-            TRACE("theory_instgen", 
-                  tout << PP(ground_clause, m) << " " <<
-                  ((is_sat==l_false)?"unsat":"sat") << "\n";);
-            return (is_sat == l_false);
-        }
-
-        bool is_homomorphic_image(expr* body) {
-            // TBD
-            return false;
-        }
-
-    };
-
-    class fo_clause_internalizer;
-    class instantiator;
-    class theory_instgen_impl;
-    typedef expr_ref_vector inst;
-
-    class instantiation_result {
-        quantifier_ref m_clause;
-        inst           m_subst;
-    public:
-        instantiation_result(ast_manager& m) : m_clause(m), m_subst(m) {}
-
-        void init(quantifier * q, const inst& subst) {
-            SASSERT(!m_clause); //we init each object at most once
-            SASSERT(m_subst.empty());
-            SASSERT(q);
-            m_clause = q;
-            m_subst.append(subst);
-        }
-        quantifier * clause() const { return m_clause; }
-        const inst& subst() const { return m_subst; }
-    };
-
-    typedef vector<instantiation_result> instantiation_result_vector;
-
-    // TBD: replace this by the substitution tree index. 
-    // It should do the trick of identifying instances and generalizers.
-    // see matching_set2..
-    //
-    class matching_set {
-        ast_manager& m;
-        vector<inst> m_inst;
-
-        //used in the has_instance function
-        mutable substitution m_subst;
-
-    public:
-        matching_set(ast_manager& m) : m(m), m_subst(m) {}
-        unsigned size() const { return m_inst.size(); }
-        inst const& operator[](unsigned i) const { return m_inst[i]; }
-
-        void insert(inst const& inst) {
-            SASSERT(m_inst.empty() || m_inst.back().size() == inst.size());
-            TRACE("theory_instgen_verbose",
-            for (unsigned i = 0; i < inst.size(); ++i) {
-                tout << PP(inst[i], m) << " ";
-            }
-            tout << "\n";
-            );
-            m_inst.push_back(inst);
-        }
-        void insert(unsigned sz, expr* const* exprs) {
-            insert(inst(m, sz, exprs));
-        }
-        void pop_insert() { m_inst.pop_back(); }
-
-        bool has_instance(inst const& inst) {
-            unsigned dont_care;
-            return has_instance(inst, dont_care);
-        }
-
-        bool has_instance(inst const& new_inst, unsigned& index) {
-            for (unsigned i = 0; i < size(); ++i) {
-                if (has_instance(new_inst, m_inst[i])) {
-                    index = i;
-                    return true;
-                }
-            }
-            return false;
-        }
-
-        class insert_inst : public trail<smt::context> {
-            matching_set& m_ms;
-        public:
-            insert_inst(matching_set& m): m_ms(m) {}
-            virtual void undo(smt::context& ctx) { m_ms.pop_insert(); }
-        };
-
-        static bool is_identity(const inst& subst) {
-            uint_set vars;
-            vars.reset();
-            unsigned sz = subst.size();
-            for(unsigned i=0; i<sz; i++) {
-                expr * val = subst[i];
-                if(!is_var(val)) { return false; }
-                unsigned var_idx = to_var(val)->get_idx();
-                if(vars.contains(var_idx)) {
-                    return false;
-                }
-                vars.insert(var_idx);
-            }
-            return true;
-        }
-
-    private:
-        // check if old_instance is an instance of new_instance.
-        bool has_instance(inst const& new_instance, inst const& old_instance) const {
-            SASSERT(new_instance.size() == old_instance.size());
-            unsigned sz = new_instance.size();
-            m_subst.reset();
-            m_subst.reserve_vars(sz);
-            m_subst.reserve_offsets(2);
-            matcher mtchr(m);
-            for(unsigned i = 0; i < sz; i++) {
-                TRACE("theory_instgen_verbose", tout << PP(new_instance[i], m) << " " << PP(old_instance[i], m) << "\n";);
-                if(!mtchr(new_instance[i], old_instance[i], m_subst)) {
-                    return false;
-                }
-            }
-            return true;
-        }
-    };
-
-
-    class matching_set2 {
-        class inst_visitor : public st_visitor {
-            bool m_found;
-        public:
-            inst_visitor(substitution& s): st_visitor(s), m_found(false) {}
-            virtual bool operator()(expr * e) {
-                m_found = true;
-                return false;
-            }
-            void reset() { m_found = false; }
-            bool found() const { return m_found; }
-        };
-
-        ast_manager&      m;
-        substitution_tree m_st;
-        func_decl_ref     m_f;
-        app_ref_vector    m_trail;
-        substitution      m_dummy;
-        inst_visitor      m_visitor;
-
-    public:
-        matching_set2(ast_manager& m) : m(m), m_st(m), m_f(m), m_trail(m), m_dummy(m), m_visitor(m_dummy) {}
-
-        void insert(inst const& inst) {
-            if (!m_f.get()) {
-                ptr_buffer<sort> domain;
-                for (unsigned i = 0; i < inst.size(); ++i) {
-                    domain.push_back(m.get_sort(inst[i]));
-                }
-                m_f = m.mk_func_decl(symbol("tuple"),inst.size(), domain.c_ptr(), m.mk_bool_sort());
-                m_trail.push_back(m.mk_app(m_f, inst.size(), inst.c_ptr()));
-                m_st.insert(m_trail.back());
-            }
-        }
-        void insert(unsigned sz, expr* const* exprs) {
-            insert(inst(m, sz, exprs));
-        }
-        void pop_insert() { 
-             m_st.erase(m_trail.back()); 
-             m_trail.pop_back(); 
-        }
-
-        bool has_instance(inst const& inst) {
-            app_ref f(m);
-            f = m.mk_app(m_f, inst.size(), inst.c_ptr());
-            m_visitor.reset();
-            m_st.inst(f, m_visitor);
-            return m_visitor.found();
-        }
-
-        class insert_inst : public trail<smt::context> {
-            matching_set& m_ms;
-        public:
-            insert_inst(matching_set& m): m_ms(m) {}
-            virtual void undo(smt::context& ctx) { m_ms.pop_insert(); }
-        };
-
-        static bool is_identity(const inst& subst) {
-            uint_set vars;
-            vars.reset();
-            unsigned sz = subst.size();
-            for(unsigned i=0; i<sz; i++) {
-                expr * val = subst[i];
-                if(!is_var(val)) { return false; }
-                unsigned var_idx = to_var(val)->get_idx();
-                if(vars.contains(var_idx)) {
-                    return false;
-                }
-                vars.insert(var_idx);
-            }
-            return true;
-        }
-    };
-
-
-    /////////////////////////
-    // inst_gen_unif_index
-    //
-
-    class inst_gen_unif_index {
-        ast_manager &     m;
-        substitution_tree m_st;
-        unsigned          m_num_vars;
-        app_ref_vector    m_ref_holder;
-        unsigned_vector   m_lim;
-
-        class collecting_visitor : public st_visitor {
-            app_ref_vector& m_acc;
-        public:
-            collecting_visitor(app_ref_vector& acc, substitution& subst)
-                : st_visitor(subst), m_acc(acc) {}
-            virtual bool operator()(expr * e) {
-                SASSERT(is_app(e));
-                m_acc.push_back(to_app(e));
-                return true;
-            }
-        };
-
-
-        class st_contains_visitor : public st_visitor {
-            expr* m_e;
-            bool m_found;
-        public:
-            st_contains_visitor(substitution& s, expr* e): st_visitor(s), m_e(e), m_found(false) {}
-            virtual bool operator()(expr* e) {
-                if (e == m_e) {
-                    m_found = true;
-                    return false;
-                }
-                return true;
-            }
-            bool found() const { return m_found; }
-        };
-
-        void debug_st(char const* cmd, app* l) {  
-            expr_ref e(m);
-            ptr_vector<sort> sorts;
-            svector<symbol> names;
-            get_free_vars(l, sorts);
-            for (unsigned i = 0; i < sorts.size(); ++i) {
-                if (!sorts[i]) {
-                    sorts[i] = m.mk_bool_sort();
-                }
-                names.push_back(symbol(i));
-            }
-            sorts.reverse();
-            if (!sorts.empty()) {
-                e = m.mk_forall(sorts.size(), sorts.c_ptr(), names.c_ptr(), l);
-            }
-            else {
-                e = l;
-            }
-            std::cout << ":" << cmd << " " << PP(e.get(),m) << "\n";
-        }
-
-    public:
-        inst_gen_unif_index(ast_manager & m) : 
-            m(m), m_st(m), m_num_vars(0), m_ref_holder(m) {}
-
-        void insert_literal(app * lit) {
-            // debug_st("st_insert", lit);
-            m_ref_holder.push_back(lit);
-            m_st.insert(lit);
-        }
-
-        void get_unifications(app * lit, app_ref_vector& res) {
-            substitution subst(m);
-            subst.reserve_vars(m_num_vars);
-            subst.reserve_offsets(m_st.get_approx_num_regs());
-            collecting_visitor visitor(res, subst);
-            // TRACE("theory_instgen", m_st.display(tout); );
-            m_st.unify(lit, visitor);
-        }
-        void reserve_num_vars(unsigned num_vars) {
-            if (num_vars > m_num_vars) m_num_vars = num_vars;
-        }
-
-        void push() {
-            m_lim.push_back(m_ref_holder.size());
-        }
-
-        void pop() {
-            unsigned sz = m_lim.back();
-            m_ref_holder.resize(sz);
-            m_lim.pop_back();
-            m_st.reset();
-        }
-
-        void pop_orig() {
-            unsigned sz = m_lim.back();
-            while (m_ref_holder.size() > sz) {
-                debug_st("st_erase", m_ref_holder.back());
-                m_st.erase(m_ref_holder.back());
-
-                substitution subst(m);
-                subst.reserve_vars(m_num_vars);
-                subst.reserve_offsets(m_st.get_approx_num_regs());
-                st_contains_visitor cv(subst, m_ref_holder.back());
-                m_st.unify(m_ref_holder.back(), cv);
-                if (cv.found()) {
-                    m_st.display(std::cout);
-                    m_st.erase(m_ref_holder.back());
-                }
-                SASSERT(!cv.found());
-                m_ref_holder.pop_back();
-            }
-            m_lim.pop_back();
-        }
-
-        void display(std::ostream& out) {
-            m_st.display(out);
-        }
-
-        bool empty() const{
-            return m_st.empty();
-        }
-    };
-
-
-    ///////////////////////////
-    // fo_clause_internalizer
-    //
-
-    class fo_clause_internalizer {
-    private:
-        typedef map<literal, app_ref_vector*, obj_hash<literal>, default_eq<literal> > literal_meaning_map;
-        typedef obj_map<expr,quantifier_ref_vector*> occurs;
-        typedef obj_map<expr,quantifier*> root_clause_map; //for any clause instance it gives us the clause from the original problem
-
-        theory_instgen_impl& m_parent;
-        expr_ref_vector      m_vars;
-        var_subst            m_subst;
-        occurs               m_occurs;
-        grounder             m_grounder;
-        /**
-           For each clause which is a result of instantiation contains the 
-           original problem clause from which it derives.
-        */
-        root_clause_map      m_root_clause_map;
-
-        
-        /**
-           For each SMT literal contains a vector of first-order literals
-           that are represented by this literal.
-        */
-        literal_meaning_map  m_literal_meanings;
-
-        /**
-           fo literals that have been internalized by this object.
-           Invariant: any app* fol in this set has a literal l such that 
-           m_literal_meanings[l].contains(fol).
-           Particularly, l==get_context().get_literal(gnd_fol) where gnd_fol 
-           is a grounded version of this literal
-        */
-        obj_hashtable<expr>  m_internalized_fo_lits;
-
-
-        ast_manager& m() const;
-        smt::context& get_context() const;
-
-        class insert_occurs_trail : public trail<smt::context> {
-            occurs&  m_occ;
-            quantifier_ref_vector* m_qs;
-            expr_ref m_lit;
-        public:
-            insert_occurs_trail(occurs& o, expr_ref& lit, quantifier* q): m_occ(o), m_qs(0), m_lit(lit) {
-                occurs::obj_map_entry* e = m_occ.insert_if_not_there2(lit,0);
-                m_qs = e->get_data().m_value;
-                if (!m_qs) {
-                    m_qs = alloc(quantifier_ref_vector, lit.get_manager());
-                    e->get_data().m_value = m_qs;
-                }
-                m_qs->push_back(q);            
-            }
-
-            virtual void undo(smt::context& ctx) {
-                SASSERT(m_qs && !m_qs->empty());
-                SASSERT(m_qs == m_occ.find_core(m_lit)->get_data().m_value);
-                m_qs->pop_back();
-                if (m_qs->empty()) {
-                    m_occ.remove(m_lit);
-                    dealloc(m_qs);
-                }
-            }
-        };
-
-        class lit_meaning_trail : public trail<smt::context> {
-            literal_meaning_map& m_map;
-            app_ref_vector* m_apps;
-            smt::literal m_smtlit;
-        public:
-
-            lit_meaning_trail(literal_meaning_map& map, ast_manager& m, smt::literal l, app* lit): 
-                m_map(map), m_smtlit(l) {             
-                literal_meaning_map::entry* e = map.insert_if_not_there2(l, 0);
-                m_apps = e->get_data().m_value;
-                if (!m_apps) {
-                    m_apps = alloc(app_ref_vector, m);
-                    e->get_data().m_value = m_apps;
-                }
-                m_apps->push_back(lit);
-            }
-
-            virtual void undo(smt::context& ctx) { 
-                SASSERT(m_apps && !m_apps->empty());
-                SASSERT(m_apps == m_map.find_core(m_smtlit)->get_data().m_value);
-                m_apps->pop_back();
-                if (m_apps->empty()) {
-                    m_map.remove(m_smtlit);
-                    dealloc(m_apps);
-                }
-            }
-        };
-
-        quantifier * get_root_clause(expr* clause) const {
-            quantifier * root;
-            if(!m_root_clause_map.find(clause, root)) {
-                SASSERT(is_forall(clause));
-                root = to_quantifier(clause);
-            }
-            return root;
-        }
-
-        void replace_by_root_clauses(ptr_vector<quantifier>& vect) const {
-            unsigned sz = vect.size();
-            for(unsigned i=0; i<sz; ++i) {
-                vect[i] = get_root_clause(vect[i]);
-            }
-        }
-
-        literal get_root_clause_control_literal(quantifier* root_clause) {
-            get_context().internalize(root_clause, true);
-            return get_context().get_literal(root_clause);
-        }
-
-        //
-        // Grounding
-        //
-
-        void insert_occurs(app * lit, quantifier* clause) {
-            SASSERT(clause);
-            TRACE("theory_instgen", tout << PP(lit, m()) << " occurs in " << PP(clause, m()) << "\n";);
-            expr_ref t(lit,m());
-            get_context().push_trail(insert_occurs_trail(m_occurs, t, clause));
-        }
-
-        literal ground_fo_literal(app * lit, quantifier* q) {
-
-            literal smt_lit;
-
-            if (is_ground(lit)) {
-                get_context().internalize(lit, true);
-                smt_lit = get_context().get_literal(lit);
-                get_context().mark_as_relevant(smt_lit); 
-                return smt_lit;
-            }
-            insert_occurs(lit, q);
-
-            app_ref grounded_lit(m());
-            m_grounder(lit, grounded_lit);
-
-            if(m_internalized_fo_lits.contains(lit)) {                
-                smt_lit = get_context().get_literal(grounded_lit);
-            }
-            else {                
-                get_context().internalize(grounded_lit, true);
-                smt_lit = get_context().get_literal(grounded_lit);
-                m_internalized_fo_lits.insert(lit);
-
-                expr_ref t(lit, m());
-                get_context().push_trail(obj_ref_trail<smt::context,ast_manager,expr>(t));
-                get_context().push_trail(insert_obj_trail<smt::context,expr>(m_internalized_fo_lits, lit));
-                get_context().push_trail(lit_meaning_trail(m_literal_meanings, m(), smt_lit, lit));
-                TRACE("theory_instgen", tout << smt_lit << " "<<  PP(grounded_lit, m())  << " |-> " << PP(lit, m()) << "\n";);
-            }
-            get_context().mark_as_relevant(smt_lit); 
-            return smt_lit;
-        }
-
-        void add_clause_to_smt(expr * clause, quantifier* root_clause, ptr_vector<quantifier> const& assumptions=ptr_vector<quantifier>());
-
-        void get_instance_clause(instantiation_result const& ir, expr_ref& res);
-
-        /**
-        return false if nothing was done
-
-        assumptions are instantiated clauses (to get a correct assumption for the SMT solver, we need
-        to convert the vector to root clauses).
-        */
-        bool simplify_clause(quantifier * clause, expr_ref& result, ptr_vector<quantifier>& assumptions);
-
-    public:
-
-        fo_clause_internalizer(theory_instgen_impl& parent): 
-            m_parent(parent),
-            m_vars(m()),
-            m_subst(m()),
-            m_grounder(m()) {
-        }
-
-        ~fo_clause_internalizer() {
-            reset_dealloc_values(m_occurs);
-        }
-
-        void get_literal_meanings(literal l, ptr_vector<app>& fo_lits) {
-            app_ref_vector* lits = 0;
-            m_literal_meanings.find(l, lits);
-            if (lits) {
-                fo_lits.append(lits->size(), lits->c_ptr());
-            }
-        }
-
-        void add_initial_clause(quantifier* q) {
-            add_clause_to_smt(q, 0);
-        }
-
-        quantifier_ref_vector* find_occurs(app * l) {
-            quantifier_ref_vector* result = 0;
-            m_occurs.find(l, result);
-            return result;
-        }                
-
-        void add_new_instance(instantiation_result const& ir) {
-            quantifier * root_clause = get_root_clause(ir.clause());
-            expr_ref inst_clause(m());
-            get_instance_clause(ir, inst_clause);
-
-            ptr_vector<quantifier> assumptions;
-            if(is_quantifier(inst_clause.get())) {
-                quantifier * q_clause = to_quantifier(inst_clause.get());
-                bool simplified = simplify_clause(q_clause, inst_clause, assumptions);
-                SASSERT(simplified || assumptions.empty());
-            }
-            replace_by_root_clauses(assumptions);
-
-            if(!m_root_clause_map.contains(inst_clause)) {
-                m_root_clause_map.insert(inst_clause, root_clause);
-                get_context().push_trail(insert_obj_map<smt::context,expr,quantifier*>(m_root_clause_map, inst_clause));
-            }
-            add_clause_to_smt(inst_clause, root_clause, assumptions);
-        }
-    };
-
-
-    /////////////////
-    // instantiator
-    //
-
-    class instantiator {
-    private:
-        typedef quantifier clause_type;
-        typedef ptr_vector<clause_type> clause_vector;
-        typedef obj_map<quantifier,matching_set*> matching_sets;
-
-        ast_manager&            m;
-        theory_instgen_impl&    m_parent;
-        fo_clause_internalizer& m_internalizer;
-        inst_gen_unif_index     m_unif_index;
-        matching_sets           m_matching;
-        unifier                 m_unifier; //used in the unify method, but we don't want to recreate over and over
-
-        class var_rename_rewriter_cfg : public default_rewriter_cfg {
-            ast_manager& m;
-            u_map<unsigned> m_index_rename;
-        public:
-            var_rename_rewriter_cfg(ast_manager& m) : m(m) {}
-
-            bool get_subst(expr * s, expr * & t, proof * & t_pr) {
-                if (is_var(s)) {
-                    unsigned idx = to_var(s)->get_idx();
-                    unsigned new_idx = 0;
-                    if (!m_index_rename.find(idx, new_idx)) {
-                        new_idx = m_index_rename.size();
-                        m_index_rename.insert(idx, new_idx);
-                    }
-                    t = m.mk_var(new_idx, to_var(s)->get_sort());
-                    return true;
-                }
-                else {
-                    return false;
-                }
-            }
-        };
-
-        static void extract_substitution(substitution& s, quantifier * q, unsigned subst_var_cnt, bool is_first_bank, expr_ref_vector& tgt) {
-            // unsigned var_increment = is_first_bank ? 0 : subst_var_cnt;
-            unsigned var_offset = is_first_bank ? 0 : 1;
-
-            unsigned deltas[2] = {0, subst_var_cnt};
-            ast_manager& m = s.get_manager();
-            unsigned var_cnt = q->get_num_decls();
-            var_rename_rewriter_cfg r_cfg(m);
-            rewriter_tpl<var_rename_rewriter_cfg> rwr(m, false, r_cfg);
-            for(unsigned i=0; i<var_cnt; i++) {
-                sort * var_sort = q->get_decl_sort(i);
-                unsigned var_idx = var_cnt-1-i;
-                var_ref v(m.mk_var(var_idx, var_sort), m);
-                expr_ref tmp(m), subst_result(m);
-                s.apply(2, deltas, expr_offset(v.get(), var_offset), tmp); 
-                rwr(tmp, subst_result);
-                tgt.push_back(subst_result);
-            }
-        }
-
-        
-        // just to be sure there's not misunderstanding with the caller, we require the res to be empty:)
-        void get_literal_occurrences(app * lit, clause_vector& res) {
-            SASSERT(res.empty());
-            quantifier_ref_vector * occurrences = m_internalizer.find_occurs(lit);
-            if(occurrences) {
-                res.append(occurrences->size(), occurrences->c_ptr());
-            }
-        }        
-
-        /**
-           check substitution wrt dismatching constraints of clause
-           (variable offset is to deal with how variable banks are shifted on each 
-           other in the substitution)
-        */
-        bool is_allowed_instantiation(clause_type * clause, const inst& subst) {
-            matching_set * ms;
-            return !m_matching.find(clause, ms) || !ms->has_instance(subst);
-        }
-
-        class new_ms : public trail<smt::context> {
-            matching_sets& m_ms;
-            matching_set*  m_s;
-            quantifier*    m_q;
-        public:
-            new_ms(matching_sets& m, matching_set* s, quantifier* q): m_ms(m), m_s(s), m_q(q) {}
-            virtual void undo(smt::context& ctx) { dealloc(m_s); m_ms.remove(m_q); }
-        };
-
-        // add instantiating substitution among the dismatching constraints
-        void record_instantiation(instantiation_result const& inst) {
-            quantifier * cl = inst.clause();
-            matching_set * ms;
-            if(!m_matching.find(cl, ms)) {
-                ms = alloc(matching_set, m);
-                m_matching.insert(cl, ms);
-                get_context().push_trail(new_ms(m_matching, ms, cl));
-            }
-            ms->insert(inst.subst());
-            get_context().push_trail(matching_set::insert_inst(*ms));
-        }
-
-        void get_result_from_subst(clause_type * clause, const inst& subst, instantiation_result& res) {
-            res.init(clause, subst);
-            record_instantiation(res);
-        }
-
-        void display_vector(expr_ref_vector const& v, std::ostream& out) {
-            for (unsigned i = 0; i < v.size(); ++i) {
-                out << PP(v[i], m) << " ";
-            }
-            out << "\n";
-        }
-
-
-        void add_lit(literal lit) {
-            ptr_vector<app> fo_lits;
-            m_internalizer.get_literal_meanings(lit, fo_lits);
-            expr_ref e(m);
-            get_context().literal2expr(lit, e);
-            if (is_ground(e.get())) {
-                fo_lits.push_back(to_app(e));
-            }
-            for (unsigned i = 0; i < fo_lits.size(); ++i) {
-                app * fol = fo_lits[i];
-                m_unif_index.insert_literal(fol);
-            }
-        }
-
-        void mk_folit_neg(app * lit, app_ref& res) {
-            expr * arg;
-            if(m.is_not(lit, arg)) {
-                SASSERT(is_app(arg));
-                res = to_app(arg);
-            }
-            else {
-                res = m.mk_not(lit);
-            }
-        }
-
-        ast_manager& get_manager() const;
-        context& get_context() const;
-
-    public:
-        instantiator(fo_clause_internalizer& internalizer, theory_instgen_impl& parent, ast_manager& m) : 
-            m(m), 
-            m_parent(parent),
-            m_internalizer(internalizer),
-            m_unif_index(m),
-            m_unifier(m) {}
-        
-        ~instantiator() {
-            reset_dealloc_values(m_matching);
-        }
-
-        bool unif_is_empty() const {
-            return m_unif_index.empty();
-        }
-
-        void display(std::ostream& out) {
-            m_unif_index.display(out);
-        }
-
-        void add_true_lit(literal lit) { 
-            add_lit(lit); 
-        }
-
-        void push() { 
-            m_unif_index.push(); 
-        }
-
-        void pop() { 
-            m_unif_index.pop(); 
-        }
-
-        void reserve_num_vars(unsigned num_vars) {
-            m_unif_index.reserve_num_vars(num_vars);
-        }
-
-        bool instantiate_clauses(
-            app * lit1, clause_type * clause1, 
-            app * lit2, clause_type * clause2, 
-            instantiation_result_vector& result);
-
-        bool instantiate_clause(
-            app * lit1, clause_type * clause1, app * lit2, 
-            instantiation_result_vector& result);
-
-        void do_instantiating(literal lit, instantiation_result_vector& res) {
-            ptr_vector<app> folits;
-            clause_vector   folit_clauses; // clauses in which the first-order literal appears
-            app_ref_vector  unifs(m);      // unifying complementary literals
-            clause_vector   comp_clauses;  // clauses in which the unifying complementary literal appears
-
-            m_internalizer.get_literal_meanings(lit, folits);
-
-            while(!folits.empty()) {
-                app * folit = folits.back();
-                
-                folits.pop_back();
-                folit_clauses.reset();
-                get_literal_occurrences(folit, folit_clauses);
-                SASSERT(!folit_clauses.empty()); //if we have a literal it should be in some clause (or not?)
-
-                SASSERT(folit->get_ref_count() > 0);
-                app_ref complementary(m);
-                mk_folit_neg(folit, complementary);
-                m_unif_index.get_unifications(complementary, unifs);
-
-                while(!unifs.empty()) {
-                    app * comp_lit = unifs.back();
-                    unifs.pop_back();
-                    SASSERT(comp_lit->get_ref_count() > 0);
-                    comp_clauses.reset();
-                    get_literal_occurrences(comp_lit, comp_clauses);
-                    TRACE("theory_instgen", tout << "Literal " << lit << " meaning: " << PP(folit, m) << "\n";
-                                            tout << "Unifies with: " << PP(comp_lit, m) << "\n";);
-                    //
-                    //if a literal is in the unification index (i.e. was assigned true sometime before),
-                    //it should be in some clause or it is a ground literal.
-
-                    //iterate through all clauses that contain the query literal
-                    //
-                    clause_vector::const_iterator fc_end = folit_clauses.end();
-                    for(clause_vector::const_iterator fc_it = folit_clauses.begin(); fc_it!=fc_end; ++fc_it) {
-
-                        //iterate through all clauses that contain the complementary unifying literal
-                        clause_vector::const_iterator end = comp_clauses.end();
-                        for(clause_vector::const_iterator it = comp_clauses.begin(); it!=end; ++it) {
-
-                            instantiate_clauses(folit, *fc_it, comp_lit, *it, res);
-                        }
-                        if (comp_clauses.empty()) {
-                            instantiate_clause(folit, *fc_it, comp_lit, res);
-                        }
-                    }
-                }
-                complementary.reset();
-            }
-        }
-    };
-
-
-    ///////////////////////////
-    // theory_instgen_impl
-    //
-
-    class theory_instgen_impl : public theory_instgen {
-
-        friend class instantiator;
-        friend class fo_clause_internalizer;
-
-        struct stats {
-            unsigned m_num_axioms;
-            unsigned m_num_subsumptions;
-            unsigned m_num_pruned;
-            stats() { memset(this, 0, sizeof(*this)); }            
-        };
-
-        ast_manager&           m_manager;
-        smt_params&      m_params;
-        fo_clause_internalizer m_internalizer;
-        instantiator           m_instantiator;
-        clause_subsumption     m_subsumer;
-        stats                 m_stats;
-
-        final_check_status instantiate_all_possible() {
-            // traverse instantiation queue and create initial instances.
-
-            ast_manager& m = get_manager();
-            context& ctx   = get_context();
-            instantiation_result_vector generated_clauses;
-            unsigned bv_cnt = ctx.get_num_bool_vars();
-
-            m_instantiator.push();
-
-            TRACE("theory_instgen",
-                tout << "Literals:\n";
-                for (unsigned v = 0; v < bv_cnt; ++v) {
-                    if (l_undef == ctx.get_assignment(v)) continue;
-                    literal lit(v, ctx.get_assignment(v) == l_false);
-                    expr_ref e(m); 
-                    ctx.literal2expr(lit, e); 
-                    tout << PP(e.get(),m) << "\n";
-                }
-            );
-
-            SASSERT(m_instantiator.unif_is_empty());
-
-            for(unsigned bvi=0; bvi < bv_cnt; ++bvi) {
-                lbool asgn_val = ctx.get_assignment(bvi);
-                if(asgn_val==l_undef) {
-                    continue;
-                }
-                literal lit(bvi, asgn_val==l_false);
-                m_instantiator.add_true_lit(lit);
-                m_instantiator.do_instantiating(lit, generated_clauses);                                
-            }
-
-            bool change = !generated_clauses.empty();
-
-            while(!generated_clauses.empty()) {
-                m_internalizer.add_new_instance(generated_clauses.back());
-                generated_clauses.pop_back();
-            }
-
-            m_instantiator.pop();
-
-            return change?FC_CONTINUE:FC_DONE;
-        }
-
-
-    public:
-        theory_instgen_impl(ast_manager& m, smt_params& p):            
-            theory_instgen(m.get_family_id("inst_gen")),
-            m_manager(m),
-            m_params(p),
-            m_internalizer(*this),
-            m_instantiator(m_internalizer, *this, m),
-            m_subsumer(m, p)
-        {}
-
-        ast_manager& m() { return m_manager; }
-
-        virtual void internalize_quantifier(quantifier* q) {
-            TRACE("theory_instgen", tout << PP(q, m()) << "\n";);
-            context& ctx = get_context();
-            if (!ctx.b_internalized(q)) {
-                bool_var v = ctx.mk_bool_var(q);
-                ctx.set_var_theory(v, get_id());      
-                m_instantiator.reserve_num_vars(q->get_num_decls());
-            }
-        }
-
-        virtual bool internalize_atom(app * atom, bool gate_ctx) {      
-            UNREACHABLE();
-            return false;
-        }
-
-        virtual bool internalize_term(app * term) {
-            UNREACHABLE();
-            return false;
-        }
-
-        virtual void new_eq_eh(theory_var v1, theory_var v2) {}
-
-        virtual void new_diseq_eh(theory_var v1, theory_var v2) {}
-
-        virtual theory * mk_fresh(context * new_ctx) {
-            return alloc(theory_instgen_impl, get_manager(), m_params);
-        }
-
-        virtual void assign_eh(bool_var v, bool is_true) {
-            context& ctx = get_context();
-            expr* e = ctx.bool_var2expr(v);
-            if (is_quantifier(e)) {
-                if (is_true) {
-                    m_internalizer.add_initial_clause(to_quantifier(e));
-                }
-                else {
-                    // TBD: handle existential force later.
-                }
-            }
-        }
-
-        virtual final_check_status final_check_eh() {
-            TRACE("theory_instgen", tout << "Final check\n";);
-            return instantiate_all_possible();
-        }
-
-        virtual void init_model(smt::model_generator & m) { }
-        
-        virtual smt::model_value_proc * mk_value(smt::enode * n, smt::model_generator & m) {
-            UNREACHABLE();
-            return 0;
-        }
-        
-        virtual void relevant_eh(app * n) { }
-
-        virtual void push_scope_eh() {
-            m_subsumer.push();
-        }
-
-        virtual void pop_scope_eh(unsigned num_scopes) {
-            m_subsumer.pop(num_scopes);
-        }
-
-        virtual void collect_statistics(::statistics & st) const {
-            st.update("inst axiom", m_stats.m_num_axioms);
-            st.update("inst subsump", m_stats.m_num_subsumptions);
-        }
-
-        void inc_subsumptions() {
-            ++m_stats.m_num_subsumptions;
-        }
-
-        void inc_axioms() {
-            ++m_stats.m_num_axioms;
-        }
-
-        void inc_pruned() {
-            ++m_stats.m_num_pruned;
-        }
-
-    };
-
-    theory_instgen* mk_theory_instgen(ast_manager& m, smt_params& p) { 
-        return alloc(theory_instgen_impl, m, p); 
-    }
-
-    ast_manager& instantiator::get_manager() const {
-        return m_parent.m();
-    }
-
-    smt::context& instantiator::get_context() const {
-        return m_parent.get_context();
-    }
-
-    bool instantiator::instantiate_clauses(
-        app * lit1, clause_type * clause1, 
-        app * lit2, clause_type * clause2, 
-        instantiation_result_vector& result) {
-        TRACE("theory_instgen", tout << PP(lit1, m) << " " << PP(clause1, m) << "\n";
-              tout << PP(lit2, m) << " " << PP(clause2, m) << "\n";);
-        substitution subst(m);
-        unsigned var_cnt = std::max(clause1->get_num_decls(), clause2->get_num_decls());
-        subst.reserve(2, var_cnt);
-        //don't trust there offset values too much, it's just what i expect the substitution does:)
-        app_ref complementary(m);
-        mk_folit_neg(lit1, complementary);
-        TRUSTME(m_unifier(complementary, lit2, subst));
-        
-        inst subst1(m);
-        extract_substitution(subst, clause1, var_cnt, true, subst1);
-        inst subst2(m);
-        extract_substitution(subst, clause2, var_cnt, false, subst2);
-        
-        bool s1_identity = matching_set::is_identity(subst1);
-        bool s2_identity = matching_set::is_identity(subst2);
-        
-        if((!s1_identity && !is_allowed_instantiation(clause1, subst1)) || 
-           (!s2_identity && !is_allowed_instantiation(clause2, subst2))) {
-            TRACE("theory_instgen", 
-                  tout << "Pruned instantiation\n";
-                  tout << PP(clause1, m) << "\n";
-                  display_vector(subst1, tout);
-                  tout << PP(clause2, m) << "\n";
-                  display_vector(subst2, tout);
-                  );
-            m_parent.inc_pruned();
-            return false;
-        }            
-        
-        //
-        // both substitutions cannot be identity as then the two complementary
-        // literals would correspond to the same SAT solver variable
-        //
-        SASSERT(!s1_identity || !s2_identity);
-        
-        if(!s1_identity) {
-            instantiation_result res1(m);
-            get_result_from_subst(clause1, subst1, res1);
-            result.push_back(res1);
-        }
-        
-        if(!s2_identity) {
-            instantiation_result res2(m);
-            get_result_from_subst(clause2, subst2, res2);
-            result.push_back(res2);
-        }
-        return true;
-    }
-
-    // literal lit2 is ground. It is not associated with a clause.
-    // literal lit1 is associatd with a non-ground clause.
-    bool instantiator::instantiate_clause(
-        app * lit1, clause_type * clause1, app * lit2, 
-        instantiation_result_vector& result) {
-        TRACE("theory_instgen", tout << PP(lit1, m) << " " << PP(clause1, m) << "\n";
-              tout << PP(lit2, m) << "\n";);
-        if (!is_ground(lit2)) {
-            // TBD: remove. Debug code.
-            std::cout << PP(lit1, m) << " " << PP(clause1, m) << "\n";
-            std::cout << PP(lit2, m) << "\n";
-            m_unif_index.display(std::cout);
-        }
-        SASSERT(is_ground(lit2));
-        substitution subst(m);
-        unsigned var_cnt = clause1->get_num_decls();
-        subst.reserve(2, var_cnt);            
-        app_ref complementary(m);
-        mk_folit_neg(lit1, complementary);
-        
-        TRUSTME(m_unifier(complementary, lit2, subst));
-        
-        inst subst1(m);            
-        extract_substitution(subst, clause1, var_cnt, true, subst1);
-        
-        if(matching_set::is_identity(subst1) ||
-           !is_allowed_instantiation(clause1, subst1)) { 
-            TRACE("theory_instgen", 
-                  tout << "Pruned instantiation\n";
-                  tout << PP(clause1, m) << "\n";
-                  display_vector(subst1, tout);
-                  );
-            m_parent.inc_pruned();
-            return false;
-        }            
-        
-        instantiation_result res1(m);
-        get_result_from_subst(clause1, subst1, res1);
-        result.push_back(res1);
-        return true;
-    }
-
-
-    //--------------------------
-    //
-    // fo_clause_internalizer
-    //
-    //--------------------------
-
-    smt::context& fo_clause_internalizer::get_context() const {
-        return m_parent.get_context();
-    }
-
-    ast_manager& fo_clause_internalizer::m() const {
-        return m_parent.m();
-    }
-
-    bool fo_clause_internalizer::simplify_clause(quantifier * clause, expr_ref& result, ptr_vector<quantifier>& assumptions) {
-        m_parent.m_subsumer.simplify(clause, result, assumptions);
-        bool change = clause!=result.get();
-        if (change) {
-            m_parent.inc_subsumptions(); 
-        }
-        return change;
-    }
-
-    void fo_clause_internalizer::get_instance_clause(instantiation_result const& ir, expr_ref& res) {
-        expr * orig_cl = ir.clause()->get_expr();
-        SASSERT(is_app(orig_cl));
-
-        expr_ref res_inner(m()); //the clause after substitution, we might still need to quantify it
-        m_subst(orig_cl, ir.subst().size(), ir.subst().c_ptr(), res_inner);
-        SASSERT(is_app(res_inner.get()));
-
-        if(is_ground(res_inner.get())) {
-            res = res_inner;
-            return; //we made it ground!
-        }
-
-        ptr_vector<sort> free_var_sorts;
-        svector<symbol> quant_names;
-        get_free_vars(res_inner.get(), free_var_sorts);
-        unsigned free_var_cnt = free_var_sorts.size();
-        for(unsigned i=0; i<free_var_cnt; i++) {
-            if(!free_var_sorts[i]) {
-                free_var_sorts[i] = m().mk_bool_sort(); //get a dummy variable
-            }
-            quant_names.push_back(symbol(free_var_cnt-i-1));
-        }
-        free_var_sorts.reverse();
-
-        quantifier_ref q_with_unused(m().mk_quantifier(true, free_var_cnt, free_var_sorts.c_ptr(), quant_names.c_ptr(), res_inner.get()), m());
-        elim_unused_vars(m(), q_with_unused, res);
-    }
-
-    /**
-       Clause can be either ground (app) or non-ground (quantifier). Root clause 
-       should be the original input clause from which the current clause was 
-       instantiated, or zero if this clause is initial
-    */
-    void fo_clause_internalizer::add_clause_to_smt(expr * clause, quantifier* root_clause, ptr_vector<quantifier> const& assumptions) {
-        SASSERT(!root_clause || root_clause->is_forall());
-        SASSERT(is_quantifier(clause) || root_clause);
-        context& ctx = get_context();
-        buffer<literal> lits;
-        ptr_buffer<expr> todo;
-
-        bool is_q_clause = is_quantifier(clause);
-        quantifier * q_clause = is_q_clause ? to_quantifier(clause) : 0;
-        if (!root_clause) root_clause = q_clause;
-
-        lits.push_back(~get_root_clause_control_literal(root_clause));
-
-        for(unsigned i=0; i<assumptions.size(); ++i) {
-            lits.push_back(~get_root_clause_control_literal(assumptions[i]));
-        }
-
-        todo.push_back(is_q_clause?(q_clause->get_expr()):clause);
-
-        while (!todo.empty()) {
-            expr* e = todo.back();
-            todo.pop_back();
-            if (m().is_or(e)) {
-                todo.append(to_app(e)->get_num_args(), to_app(e)->get_args());
-            }
-            else if (is_app(e)) {
-                lits.push_back(ground_fo_literal(to_app(e), q_clause));
-            }
-            else {
-                SASSERT(is_var(e) || is_quantifier(e));
-                UNREACHABLE(); 
-                //by skipping part of the disjunction we may get unsound
-            }
-        }
-        TRACE("theory_instgen",
-              tout << "Axiom: \n";
-              for (unsigned i = 0; i < lits.size(); ++i) {
-                  expr_ref e(m());
-                  get_context().literal2expr(lits[i], e);
-                  tout << PP(e.get(), m()) << "\n";
-              }
-              );
-        m_parent.inc_axioms();
-        ctx.mk_th_axiom(m_parent.get_id(), lits.size(), lits.c_ptr());
-    }
-
-
-};
diff --git a/src/smt/theory_instgen.h b/src/smt/theory_instgen.h
deleted file mode 100644
index c32636e9b..000000000
--- a/src/smt/theory_instgen.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/*++
-Copyright (c) 2011 Microsoft Corporation
-
-Module Name:
-
-    theory_instgen.h
-
-Abstract:
-
-    InstGen (iProver) style theory solver.
-    It provides an instantiation based engine
-    based on InstGen methods together with
-    unit propagation.
-
-
-Author:
-
-    Krystof Hoder (t-khoder) 
-    Nikolaj Bjorner (nbjorner) 2011-10-6
-
-Revision History:
-
---*/
-#ifndef _THEORY_INST_GEN_H_
-#define _THEORY_INST_GEN_H_
-
-#include "smt_theory.h"
-#include "smt_params.h"
-
-namespace smt {
-
-    class theory_instgen : public theory {
-    public:
-        theory_instgen(family_id fid) : theory(fid) {}
-        virtual ~theory_instgen() {}
-        virtual void internalize_quantifier(quantifier* q) = 0;
-        virtual char const * get_name() const { return "instgen"; }
-    };
-
-    theory_instgen* mk_theory_instgen(ast_manager& m, smt_params& p);
-
-};
-
-#endif /* _THEORY_INST_GEN_H_ */
-
diff --git a/src/smt/theory_seq_empty.h b/src/smt/theory_seq_empty.h
index ef3924603..d5468df28 100644
--- a/src/smt/theory_seq_empty.h
+++ b/src/smt/theory_seq_empty.h
@@ -32,7 +32,7 @@ namespace smt {
         virtual theory* mk_fresh(context*) { return alloc(theory_seq_empty, get_manager()); }
         virtual char const * get_name() const { return "seq-empty"; }
     public:
-        theory_seq_empty(ast_manager& m):theory(m.get_family_id("seq")), m_used(false) {}
+        theory_seq_empty(ast_manager& m):theory(m.mk_family_id("seq")), m_used(false) {}
     };
 
 };
diff --git a/src/smt/user_plugin/user_smt_theory.cpp b/src/smt/user_plugin/user_smt_theory.cpp
index ab4cc62c4..a2d1e4f37 100644
--- a/src/smt/user_plugin/user_smt_theory.cpp
+++ b/src/smt/user_plugin/user_smt_theory.cpp
@@ -646,7 +646,7 @@ namespace smt {
         context & ctx               = _s.get_context(); // HACK
         symbol _name(name);
         ast_manager & m             = ctx.get_manager();
-        family_id fid               = m.get_family_id(_name);
+        family_id fid               = m.mk_family_id(_name);
         user_decl_plugin * dp       = alloc(user_decl_plugin);
         m.register_plugin(fid, dp);
         simplifier & s              = ctx.get_simplifier();
diff --git a/src/solver/combined_solver.cpp b/src/solver/combined_solver.cpp
new file mode 100644
index 000000000..a98e5be49
--- /dev/null
+++ b/src/solver/combined_solver.cpp
@@ -0,0 +1,307 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    combined_solver.cpp
+
+Abstract:
+
+    Implements the solver API by combining two solvers.
+
+    This is a replacement for the strategic_solver class.
+
+Author:
+
+    Leonardo (leonardo) 2012-12-11
+
+Notes:
+
+--*/
+#include"solver.h"
+#include"scoped_timer.h"
+#include"combined_solver_params.hpp"
+#define PS_VB_LVL 15
+
+/**
+   \brief Implementation of the solver API that combines two given solvers.
+
+   The combined solver has two modes:
+       - non-incremental
+       - incremental
+   In non-incremental mode, the first solver is used.
+   In incremental mode, the second one is used.
+   
+   A timeout for the second solver can be specified.
+   If the timeout is reached, then the first solver is executed.
+
+   The object switches to incremental when:
+       - push is used
+       - assertions are peformed after a check_sat
+       - parameter ignore_solver1==false
+*/
+class combined_solver : public solver {
+public:
+    // Behavior when the incremental solver returns unknown.
+    enum inc_unknown_behavior {
+        IUB_RETURN_UNDEF,      // just return unknown
+        IUB_USE_TACTIC_IF_QF,  // invoke tactic if problem is quantifier free
+        IUB_USE_TACTIC         // invoke tactic
+    };
+
+private:
+    bool                 m_inc_mode;
+    bool                 m_check_sat_executed;
+    bool                 m_use_solver1_results;
+    ref<solver>          m_solver1;
+    ref<solver>          m_solver2;
+    // We delay sending assertions to solver 2
+    // This is relevant for big benchmarks that are meant to be solved
+    // by a non-incremental solver. 
+    bool                 m_solver2_initialized;
+
+    bool                 m_ignore_solver1;
+    inc_unknown_behavior m_inc_unknown_behavior;
+    unsigned             m_inc_timeout;
+    
+    void init_solver2_assertions() {
+        if (m_solver2_initialized)
+            return;
+        unsigned sz = m_solver1->get_num_assertions();
+        for (unsigned i = 0; i < sz; i++) {
+            m_solver2->assert_expr(m_solver1->get_assertion(i));
+        }
+        m_solver2_initialized = true;
+    }
+
+    void switch_inc_mode() {
+        m_inc_mode = true;
+        init_solver2_assertions();
+    }
+
+    struct aux_timeout_eh : public event_handler {
+        solver *        m_solver;
+        volatile bool   m_canceled;
+        aux_timeout_eh(solver * s):m_solver(s), m_canceled(false) {}
+        virtual void operator()() {
+            m_solver->cancel();
+            m_canceled = true;
+        }
+    };
+
+    void updt_local_params(params_ref const & _p) {
+        combined_solver_params p(_p);
+        m_inc_timeout    = p.solver2_timeout();
+        m_ignore_solver1 = p.ignore_solver1();
+        m_inc_unknown_behavior = static_cast<inc_unknown_behavior>(p.solver2_unknown());
+    }
+
+    bool has_quantifiers() const {
+        unsigned sz = get_num_assertions();
+        for (unsigned i = 0; i < sz; i++) {
+            if (::has_quantifiers(get_assertion(i)))
+                return true;
+        }
+        return false;
+    }
+
+    bool use_solver1_when_undef() const {
+        switch (m_inc_unknown_behavior) {
+        case IUB_RETURN_UNDEF: return false;
+        case IUB_USE_TACTIC_IF_QF: return !has_quantifiers();
+        case IUB_USE_TACTIC: return true;
+        default:
+            UNREACHABLE();
+            return false;
+        }
+    }
+
+public:
+    combined_solver(solver * s1, solver * s2, params_ref const & p) {
+        m_solver1 = s1;
+        m_solver2 = s2;
+        updt_local_params(p);
+        m_solver2_initialized = false;
+        m_inc_mode            = false;
+        m_check_sat_executed  = false;
+        m_use_solver1_results = true;
+    }
+
+    virtual void updt_params(params_ref const & p) {
+        m_solver1->updt_params(p);
+        m_solver2->updt_params(p);
+        updt_local_params(p);
+    }
+
+    virtual void collect_param_descrs(param_descrs & r) {
+        m_solver1->collect_param_descrs(r);
+        m_solver2->collect_param_descrs(r);
+        combined_solver_params::collect_param_descrs(r);
+    }
+    
+    virtual void set_produce_models(bool f) {
+        m_solver1->set_produce_models(f);
+        m_solver2->set_produce_models(f);
+    }
+    
+    virtual void assert_expr(expr * t) {
+        if (m_check_sat_executed)
+            switch_inc_mode();
+        m_solver1->assert_expr(t);
+        if (m_solver2_initialized)
+            m_solver2->assert_expr(t);
+    }
+
+    virtual void assert_expr(expr * t, expr * a) {
+        if (m_check_sat_executed)
+            switch_inc_mode();
+        m_solver1->assert_expr(t, a);
+        init_solver2_assertions();
+        m_solver2->assert_expr(t, a);
+    }
+
+    virtual void push() {
+        switch_inc_mode();
+        m_solver1->push();
+        m_solver2->push();
+    }
+    
+    virtual void pop(unsigned n) {
+        switch_inc_mode();
+        m_solver1->pop(n);
+        m_solver2->pop(n);
+    }
+
+    virtual unsigned get_scope_level() const {
+        return m_solver1->get_scope_level();
+    }
+
+    virtual lbool check_sat(unsigned num_assumptions, expr * const * assumptions) {
+        m_check_sat_executed  = true;
+
+        if (num_assumptions > 0 || // assumptions were provided
+            m_ignore_solver1)  {
+            // must use incremental solver
+            switch_inc_mode();
+            m_use_solver1_results = false;
+            return m_solver2->check_sat(num_assumptions, assumptions);
+        }
+        
+        if (m_inc_mode) {
+            if (m_inc_timeout == UINT_MAX) {
+                IF_VERBOSE(PS_VB_LVL, verbose_stream() << "(combined-solver \"using solver 2 (without a timeout)\")\n";);            
+                lbool r = m_solver2->check_sat(0, 0);
+                if (r != l_undef || !use_solver1_when_undef()) {
+                    m_use_solver1_results = false;
+                    return r;
+                }
+            }
+            else {
+                IF_VERBOSE(PS_VB_LVL, verbose_stream() << "(combined-solver \"using solver 2 (with timeout)\")\n";);            
+                aux_timeout_eh eh(m_solver2.get());
+                lbool r;
+                {
+                    scoped_timer timer(m_inc_timeout, &eh);
+                    r = m_solver2->check_sat(0, 0);
+                }
+                if ((r != l_undef || !use_solver1_when_undef()) && !eh.m_canceled) {
+                    m_use_solver1_results = false;
+                    return r;
+                }
+            }
+            IF_VERBOSE(PS_VB_LVL, verbose_stream() << "(combined-solver \"solver 2 failed, trying solver1\")\n";);                        
+        }
+        
+        IF_VERBOSE(PS_VB_LVL, verbose_stream() << "(combined-solver \"using solver 1\")\n";);
+        m_use_solver1_results = true;
+        return m_solver1->check_sat(0, 0);
+    }
+
+    virtual void set_cancel(bool f) {
+        m_solver1->set_cancel(f);
+        m_solver2->set_cancel(f);
+    }
+    
+    virtual void set_progress_callback(progress_callback * callback) {
+        m_solver1->set_progress_callback(callback);
+        m_solver2->set_progress_callback(callback);
+    }
+    
+    virtual unsigned get_num_assertions() const {
+        return m_solver1->get_num_assertions();
+    }
+
+    virtual expr * get_assertion(unsigned idx) const {
+        return m_solver1->get_assertion(idx);
+    }
+
+    virtual void display(std::ostream & out) const {
+        m_solver1->display(out);
+    }
+
+    virtual void collect_statistics(statistics & st) const {
+        if (m_use_solver1_results)
+            m_solver1->collect_statistics(st);
+        else
+            m_solver2->collect_statistics(st);
+    }
+
+    virtual void get_unsat_core(ptr_vector<expr> & r) {
+        if (m_use_solver1_results)
+            m_solver1->get_unsat_core(r);
+        else
+            m_solver2->get_unsat_core(r);
+    }
+
+    virtual void get_model(model_ref & m) {
+        if (m_use_solver1_results)
+            m_solver1->get_model(m);
+        else
+            m_solver2->get_model(m);
+    }
+
+    virtual proof * get_proof() {
+        if (m_use_solver1_results)
+            return m_solver1->get_proof();
+        else
+            return m_solver2->get_proof();
+    }
+
+    virtual std::string reason_unknown() const {
+        if (m_use_solver1_results)
+            return m_solver1->reason_unknown();
+        else
+            return m_solver2->reason_unknown();
+    }
+
+    virtual void get_labels(svector<symbol> & r) {
+        if (m_use_solver1_results)
+            return m_solver1->get_labels(r);
+        else
+            return m_solver2->get_labels(r);
+    }
+
+};
+
+
+solver * mk_combined_solver(solver * s1, solver * s2, params_ref const & p) {
+    return alloc(combined_solver, s1, s2, p);
+}
+
+class combined_solver_factory : public solver_factory {
+    scoped_ptr<solver_factory> m_f1;
+    scoped_ptr<solver_factory> m_f2;
+public:
+    combined_solver_factory(solver_factory * f1, solver_factory * f2):m_f1(f1), m_f2(f2) {}
+    virtual ~combined_solver_factory() {}
+
+    virtual solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) {
+        return mk_combined_solver((*m_f1)(m, p, proofs_enabled, models_enabled, unsat_core_enabled, logic),
+                                  (*m_f2)(m, p, proofs_enabled, models_enabled, unsat_core_enabled, logic),
+                                  p);
+    }
+};
+
+solver_factory * mk_combined_solver_factory(solver_factory * f1, solver_factory * f2) {
+    return alloc(combined_solver_factory, f1, f2);
+}
diff --git a/src/solver/combined_solver.h b/src/solver/combined_solver.h
new file mode 100644
index 000000000..2ccace7f0
--- /dev/null
+++ b/src/solver/combined_solver.h
@@ -0,0 +1,32 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    combined_solver.cpp
+
+Abstract:
+
+    Implements the solver API by combining two solvers.
+
+    This is a replacement for the strategic_solver class.
+
+Author:
+
+    Leonardo (leonardo) 2012-12-11
+
+Notes:
+
+--*/
+#ifndef _COMBINED_SOLVER_H_
+#define _COMBINED_SOLVER_H_
+
+#include"params.h"
+
+class solver;
+class solver_factory;
+
+solver * mk_combined_solver(solver * s1, solver * s2, params_ref const & p);
+solver_factory * mk_combined_solver_factory(solver_factory * f1, solver_factory * f2);
+
+#endif
diff --git a/src/solver/combined_solver_params.pyg b/src/solver/combined_solver_params.pyg
new file mode 100644
index 000000000..7e1635c16
--- /dev/null
+++ b/src/solver/combined_solver_params.pyg
@@ -0,0 +1,9 @@
+def_module_params('combined_solver', 
+                  description='combines two solvers: non-incremental (solver1) and incremental (solver2)',
+                  export=True,
+                  params=(('solver2_timeout', UINT, UINT_MAX, "fallback to solver 1 after timeout even when in incremental model"),
+                          ('ignore_solver1', BOOL, False, "if true, solver 2 is always used"),
+                          ('solver2_unknown', UINT, 1, "what should be done when solver 2 returns unknown: 0 - just return unknown, 1 - execute solver 1 if quantifier free problem, 2 - execute solver 1")
+                          ))
+
+                
diff --git a/src/solver/solver.h b/src/solver/solver.h
index 5cd3da52b..e047bace1 100644
--- a/src/solver/solver.h
+++ b/src/solver/solver.h
@@ -23,6 +23,14 @@ Notes:
 #include"progress_callback.h"
 #include"params.h"
 
+class solver;
+
+class solver_factory {
+public:
+    virtual ~solver_factory() {}
+    virtual solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) = 0;
+};
+
 /**
    \brief Abstract interface for making solvers available in the Z3
    API and front-ends such as SMT 2.0 and (legacy) SMT 1.0.
@@ -34,7 +42,6 @@ Notes:
      - statistics
      - results based on check_sat_result API
      - interruption (set_cancel)
-     - resets 
 */
 class solver : public check_sat_result {
 public:
@@ -50,12 +57,6 @@ public:
     */
     virtual void collect_param_descrs(param_descrs & r) {}
     
-    /**
-       \brief Enable/Disable proof production for this solver object.
-    
-       It is invoked before init(m, logic).
-    */
-    virtual void set_produce_proofs(bool f) {}
     /**
        \brief Enable/Disable model generation for this solver object.
 
@@ -63,23 +64,7 @@ public:
        The user may optionally invoke it after init(m, logic).
     */
     virtual void set_produce_models(bool f) {}
-    /**
-       \brief Enable/Disable unsat core generation for this solver object.
-
-       It is invoked before init(m, logic).
-    */
-    virtual void set_produce_unsat_cores(bool f) {}
     
-    /**
-       \brief Initialize the solver object with the given ast_manager and logic.
-    */
-    virtual void init(ast_manager & m, symbol const & logic) = 0;
-    
-    /**
-       \brief Reset the solver internal state. All assertions should be removed.
-    */
-    virtual void reset() = 0;
-
     /**
        \brief Add a new formula to the assertion stack.
     */
diff --git a/src/solver/solver_na2as.cpp b/src/solver/solver_na2as.cpp
index e71a9873b..9889b5872 100644
--- a/src/solver/solver_na2as.cpp
+++ b/src/solver/solver_na2as.cpp
@@ -22,8 +22,8 @@ Notes:
 #include"solver_na2as.h"
 #include"ast_smt2_pp.h"
 
-solver_na2as::solver_na2as() {
-    m_manager = 0;
+solver_na2as::solver_na2as(ast_manager & m):
+    m_manager(m) {
 }
 
 solver_na2as::~solver_na2as() {
@@ -35,23 +35,16 @@ void solver_na2as::assert_expr(expr * t, expr * a) {
         assert_expr(t);
     }
     else {
-        SASSERT(m_manager != 0);
         SASSERT(is_uninterp_const(a));
-        SASSERT(m_manager->is_bool(a));
-        TRACE("solver_na2as", tout << "asserting\n" << mk_ismt2_pp(t, *m_manager) << "\n" << mk_ismt2_pp(a, *m_manager) << "\n";);
-        m_manager->inc_ref(a);
+        SASSERT(m_manager.is_bool(a));
+        TRACE("solver_na2as", tout << "asserting\n" << mk_ismt2_pp(t, m_manager) << "\n" << mk_ismt2_pp(a, m_manager) << "\n";);
+        m_manager.inc_ref(a);
         m_assumptions.push_back(a);
-        expr_ref new_t(*m_manager);
-        new_t = m_manager->mk_implies(a, t);
+        expr_ref new_t(m_manager);
+        new_t = m_manager.mk_implies(a, t);
         assert_expr(new_t);
     }
 }
-    
-void solver_na2as::init(ast_manager & m, symbol const & logic) {
-    SASSERT(m_assumptions.empty());
-    m_manager = &m;
-    init_core(m, logic);
-}
 
 struct append_assumptions {
     ptr_vector<expr> & m_assumptions;
@@ -89,9 +82,9 @@ void solver_na2as::pop(unsigned n) {
 }
 
 void solver_na2as::restore_assumptions(unsigned old_sz) {
-    SASSERT(old_sz == 0 || m_manager != 0);
+    SASSERT(old_sz == 0);
     for (unsigned i = old_sz; i < m_assumptions.size(); i++) {
-        m_manager->dec_ref(m_assumptions[i]);
+        m_manager.dec_ref(m_assumptions[i]);
     }
     m_assumptions.shrink(old_sz);
 }
@@ -100,7 +93,3 @@ unsigned solver_na2as::get_scope_level() const {
     return m_scopes.size();
 }
 
-void solver_na2as::reset() {
-    reset_core();
-    restore_assumptions(0);
-}
diff --git a/src/solver/solver_na2as.h b/src/solver/solver_na2as.h
index eb12479fc..15750344a 100644
--- a/src/solver/solver_na2as.h
+++ b/src/solver/solver_na2as.h
@@ -25,30 +25,26 @@ Notes:
 #include"solver.h"
 
 class solver_na2as : public solver {
-    ast_manager *      m_manager;
+    ast_manager &      m_manager;
     ptr_vector<expr>   m_assumptions;
     unsigned_vector    m_scopes;
     void restore_assumptions(unsigned old_sz);
 public:
-    solver_na2as();
+    solver_na2as(ast_manager & m);
     virtual ~solver_na2as();
 
     virtual void assert_expr(expr * t, expr * a);
     virtual void assert_expr(expr * t) = 0;
     
     // Subclasses of solver_na2as should redefine the following *_core methods instead of these ones.
-    virtual void init(ast_manager & m, symbol const & logic);
     virtual lbool check_sat(unsigned num_assumptions, expr * const * assumptions);
     virtual void push();
     virtual void pop(unsigned n);
     virtual unsigned get_scope_level() const;
-    virtual void reset();
 protected:
-    virtual void init_core(ast_manager & m, symbol const & logic) = 0;
     virtual lbool check_sat_core(unsigned num_assumptions, expr * const * assumptions) = 0;
     virtual void push_core() = 0;
     virtual void pop_core(unsigned n) = 0;
-    virtual void reset_core() = 0;
 };
 
 
diff --git a/src/solver/strategic_solver.cpp b/src/solver/strategic_solver.cpp
deleted file mode 100644
index 40d77066e..000000000
--- a/src/solver/strategic_solver.cpp
+++ /dev/null
@@ -1,533 +0,0 @@
-/*++
-Copyright (c) 2011 Microsoft Corporation
-
-Module Name:
-
-    strategic_solver.h
-
-Abstract:
-
-    Strategies -> Solver
-
-Author:
-
-    Leonardo (leonardo) 2011-05-19
-
-Notes:
-
---*/
-#include"strategic_solver.h"
-#include"scoped_timer.h"
-#include"ast_smt2_pp.h"
-
-// minimum verbosity level for portfolio verbose messages
-#define PS_VB_LVL 15
-
-    
-strategic_solver::ctx::ctx(ast_manager & m):
-    m_assertions(m), 
-    m_assertion_names(m) {
-    }    
-
-strategic_solver::strategic_solver():
-    m_manager(0),
-    m_force_tactic(false),
-    m_inc_mode(false),
-    m_check_sat_executed(false),
-    m_inc_solver(0),
-    m_inc_solver_timeout(UINT_MAX),
-    m_inc_unknown_behavior(IUB_USE_TACTIC_IF_QF),
-    m_default_fct(0),
-    m_curr_tactic(0),
-    m_proof(0),
-    m_core(0),
-    m_callback(0) {
-    m_use_inc_solver_results = false;
-    DEBUG_CODE(m_num_scopes = 0;);
-    m_produce_proofs = false;
-    m_produce_models = false;
-    m_produce_unsat_cores = false;
-    m_auto_config = true;
-}
-
-strategic_solver::~strategic_solver() {
-    SASSERT(!m_curr_tactic);
-    dictionary<tactic_factory*>::iterator it  = m_logic2fct.begin();
-    dictionary<tactic_factory*>::iterator end = m_logic2fct.end();
-    for (; it != end; ++it) {
-        dealloc(it->m_value);
-    }
-    if (m_proof)
-        m().dec_ref(m_proof);
-    if (m_core)
-        m().dec_ref(m_core);
-}
-
-bool strategic_solver::has_quantifiers() const {
-    unsigned sz = get_num_assertions();
-    for (unsigned i = 0; i < sz; i++) {
-        if (::has_quantifiers(get_assertion(i)))
-            return true;
-    }
-    return false;
-}
-
-/**
-   \brief Return true if a tactic should be used when the incremental solver returns unknown.
-*/
-bool strategic_solver::use_tactic_when_undef() const {
-    switch (m_inc_unknown_behavior) {
-    case IUB_RETURN_UNDEF: return false;
-    case IUB_USE_TACTIC_IF_QF: return !has_quantifiers();
-    case IUB_USE_TACTIC: return true;
-    default:
-        UNREACHABLE();
-        return false;
-    }
-}
-
-void strategic_solver::set_inc_solver(solver * s) {
-    SASSERT(m_inc_solver == 0);
-    SASSERT(m_num_scopes == 0);
-    m_inc_solver = s;
-    if (m_callback)
-        m_inc_solver->set_progress_callback(m_callback);
-}
-
-void strategic_solver::updt_params(params_ref const & p) {
-    if (m_inc_solver)
-        m_inc_solver->updt_params(p);
-    m_params = p;
-    m_auto_config = p.get_bool("auto_config", true);
-}
-
-void strategic_solver::collect_param_descrs(param_descrs & r) {
-    if (m_inc_solver)
-        m_inc_solver->collect_param_descrs(r);
-}
-
-/**
-   \brief Set a timeout for each check_sat query that is processed by the inc_solver.
-   timeout == UINT_MAX means infinite
-   After the timeout a strategy is used.
-*/
-void strategic_solver::set_inc_solver_timeout(unsigned timeout) {
-    m_inc_solver_timeout = timeout;
-}
-
-/**
-   \brief Set the default tactic factory.
-   It is used if there is no tactic for a given logic.
-*/
-void strategic_solver::set_default_tactic(tactic_factory * fct) {
-    m_default_fct = fct;
-}
-
-/**
-   \brief Set a tactic factory for a given logic.
-*/
-void strategic_solver::set_tactic_for(symbol const & logic, tactic_factory * fct) {
-    tactic_factory * old_fct;
-    if (m_logic2fct.find(logic, old_fct)) {
-        dealloc(old_fct);
-    }
-    m_logic2fct.insert(logic, fct);
-}
-
-void strategic_solver::init(ast_manager & m, symbol const & logic) {
-    m_manager = &m;
-    m_logic   = logic;
-    if (m_inc_mode) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->init(m, logic);
-    }
-    m_ctx = alloc(ctx, m);
-    TRACE("strategic_solver", tout << "strategic_solver was initialized.\n";);
-}
-
-unsigned strategic_solver::get_num_assertions() const {
-    if (m_ctx == 0)
-        return 0;
-    return m_ctx->m_assertions.size();
-}
-
-expr * strategic_solver::get_assertion(unsigned idx) const {
-    SASSERT(m_ctx);
-    return m_ctx->m_assertions.get(idx);
-}
-
-expr * strategic_solver::get_assertion_name(unsigned idx) const {
-    SASSERT(m_ctx);
-    SASSERT(m_produce_unsat_cores);
-    return m_ctx->m_assertion_names.get(idx);
-}
-
-void strategic_solver::set_produce_proofs(bool f) { 
-    m_produce_proofs = f; 
-    // do not need to propagate to inc_solver since flag cannot be changed after initialization
-}
-
-void strategic_solver::set_produce_models(bool f) { 
-    m_produce_models = f; 
-    if (m_inc_solver) 
-        m_inc_solver->set_produce_models(f);
-}
-
-void strategic_solver::set_produce_unsat_cores(bool f) { 
-    m_produce_unsat_cores = f; 
-    // do not need to propagate to inc_solver since flag cannot be changed after initialization
-}
-
-// delayed inc solver initialization
-void strategic_solver::init_inc_solver() {
-    if (m_inc_mode) 
-        return; // solver was already initialized
-    if (!m_inc_solver)
-        return; // inc solver was not installed
-    m_inc_mode = true;
-    m_inc_solver->set_produce_proofs(m_produce_proofs);
-    m_inc_solver->set_produce_models(m_produce_models);
-    m_inc_solver->set_produce_unsat_cores(m_produce_unsat_cores);
-    m_inc_solver->init(m(), m_logic);
-    unsigned sz = get_num_assertions();
-    if (m_produce_unsat_cores) {
-        SASSERT(m_ctx->m_assertions.size() == m_ctx->m_assertion_names.size());
-        for (unsigned i = 0; i < sz; i++) {
-            m_inc_solver->assert_expr(get_assertion(i), get_assertion_name(i));
-        }
-    }
-    else {
-        for (unsigned i = 0; i < sz; i++) {
-            m_inc_solver->assert_expr(get_assertion(i));
-        }
-    }
-}
-
-void strategic_solver::collect_statistics(statistics & st) const {
-    if (m_use_inc_solver_results) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->collect_statistics(st);
-    }
-    else {
-        if (m_curr_tactic) 
-            m_curr_tactic->collect_statistics(st); // m_curr_tactic is still being executed.
-        else
-            st.copy(m_stats);
-    }
-}
-
-void strategic_solver::reset() {
-    m_ctx      = 0;
-    m_logic    = symbol::null;
-    m_inc_mode = false;
-    m_check_sat_executed = false;
-    if (m_inc_solver)
-        m_inc_solver->reset();
-    SASSERT(!m_curr_tactic);
-    m_use_inc_solver_results = false;
-    reset_results();
-}
-
-void strategic_solver::reset_results() {
-    m_use_inc_solver_results = false;
-    m_model = 0;
-    if (m_proof) {
-        m().dec_ref(m_proof);
-        m_proof = 0;
-    }
-    if (m_core) {
-        m().dec_ref(m_core);
-        m_core = 0;
-    }
-    m_reason_unknown.clear();
-    m_stats.reset();
-}
-
-void strategic_solver::assert_expr(expr * t) {
-    if (m_check_sat_executed && !m_inc_mode) {
-        // a check sat was already executed --> switch to incremental mode
-        init_inc_solver();
-        SASSERT(m_inc_solver == 0 || m_inc_mode);
-    }
-    if (m_inc_mode) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->assert_expr(t);
-    }
-    SASSERT(m_ctx);
-    m_ctx->m_assertions.push_back(t);
-    if (m_produce_unsat_cores)
-        m_ctx->m_assertion_names.push_back(0);
-}
-
-void strategic_solver::assert_expr(expr * t, expr * a) {
-    if (m_check_sat_executed && !m_inc_mode) {
-        // a check sat was already executed --> switch to incremental mode
-        init_inc_solver();
-        SASSERT(m_inc_solver == 0 || m_inc_mode);
-    }
-    if (m_inc_mode) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->assert_expr(t, a);
-    }
-    SASSERT(m_ctx);
-    m_ctx->m_assertions.push_back(t);
-    if (m_produce_unsat_cores)
-        m_ctx->m_assertion_names.push_back(a);
-}
-
-void strategic_solver::push() {
-    DEBUG_CODE(m_num_scopes++;);
-    init_inc_solver();
-    if (m_inc_solver)
-        m_inc_solver->push();
-    m_ctx->m_scopes.push_back(m_ctx->m_assertions.size());
-}
-
-void strategic_solver::pop(unsigned n) {
-    DEBUG_CODE({
-            SASSERT(n <= m_num_scopes);
-            m_num_scopes -= n;
-        });
-    init_inc_solver();
-    if (m_inc_solver)
-        m_inc_solver->pop(n);
-
-    SASSERT(m_ctx);
-    unsigned new_lvl = m_ctx->m_scopes.size() - n;
-    unsigned old_sz  = m_ctx->m_scopes[new_lvl];
-    m_ctx->m_assertions.shrink(old_sz);
-    if (m_produce_unsat_cores)
-        m_ctx->m_assertion_names.shrink(old_sz);
-    m_ctx->m_scopes.shrink(new_lvl);
-}
-
-unsigned strategic_solver::get_scope_level() const {
-    if (m_ctx == 0)
-        return 0;
-    return m_ctx->m_scopes.size();
-}
-
-struct aux_timeout_eh : public event_handler {
-    solver *        m_solver;
-    volatile bool   m_canceled;
-    aux_timeout_eh(solver * s):m_solver(s), m_canceled(false) {}
-    virtual void operator()() {
-        m_solver->cancel();
-        m_canceled = true;
-    }
-};
-
-struct strategic_solver::mk_tactic {
-    strategic_solver *  m_solver;
-
-    mk_tactic(strategic_solver * s, tactic_factory * f, params_ref const & p):m_solver(s) {
-        ast_manager & m = s->m();
-        tactic * tct = (*f)(m, p);
-        tct->set_logic(s->m_logic);
-        if (s->m_callback)
-            tct->set_progress_callback(s->m_callback);
-        #pragma omp critical (strategic_solver) 
-        {
-            s->m_curr_tactic = tct;
-        }
-    }
-
-    ~mk_tactic() {
-        #pragma omp critical (strategic_solver)
-        {
-            m_solver->m_curr_tactic = 0;
-        }
-    }
-};
-
-tactic_factory * strategic_solver::get_tactic_factory() const {
-    tactic_factory * f = 0;
-    if (m_logic2fct.find(m_logic, f))
-        return f;
-    return m_default_fct.get();
-}
-
-lbool strategic_solver::check_sat_with_assumptions(unsigned num_assumptions, expr * const * assumptions) {
-    if (!m_inc_solver) {
-        IF_VERBOSE(PS_VB_LVL, verbose_stream() << "incremental solver was not installed, returning unknown...\n";);
-        m_use_inc_solver_results = false;
-        m_reason_unknown         = "incomplete";
-        return l_undef; 
-    }
-    init_inc_solver();
-    m_use_inc_solver_results = true;
-    TRACE("strategic_solver", tout << "invoking inc_solver with " << num_assumptions << " assumptions\n";);
-    return m_inc_solver->check_sat(num_assumptions, assumptions);
-}
-
-lbool strategic_solver::check_sat(unsigned num_assumptions, expr * const * assumptions) {
-    TRACE("strategic_solver", tout << "assumptions at strategic_solver:\n";
-          for (unsigned i = 0; i < num_assumptions; i++) {
-              tout << mk_ismt2_pp(assumptions[i], m()) << "\n";
-          }
-          tout << "m_produce_unsat_cores: " << m_produce_unsat_cores << ", m_inc_mode: " << m_inc_mode << "\n";);
-    reset_results();
-    m_check_sat_executed = true;
-    if (num_assumptions > 0 || // assumptions were provided
-        (!m_auto_config && !m_force_tactic) // auto config and force_tactic are turned off
-        ) {
-        // must use incremental solver
-        return check_sat_with_assumptions(num_assumptions, assumptions);
-    }
-
-    tactic_factory * factory = get_tactic_factory();
-    if (factory == 0)
-        init_inc_solver(); // try to switch to incremental solver
-    
-    if (m_inc_mode) {
-        SASSERT(m_inc_solver);
-        unsigned timeout = m_inc_solver_timeout;
-        if (factory == 0)
-            timeout = UINT_MAX; // there is no tactic available
-        if (timeout == UINT_MAX) {
-            IF_VERBOSE(PS_VB_LVL, verbose_stream() << "using incremental solver (without a timeout).\n";);            
-            m_use_inc_solver_results = true;
-            lbool r = m_inc_solver->check_sat(0, 0);
-            if (r != l_undef || factory == 0 || !use_tactic_when_undef()) {
-                m_use_inc_solver_results = true;
-                return r;
-            }
-        }
-        else {
-            IF_VERBOSE(PS_VB_LVL, verbose_stream() << "using incremental solver (with timeout).\n";);            
-            SASSERT(factory != 0);
-            aux_timeout_eh eh(m_inc_solver.get());
-            lbool r;
-            {
-                scoped_timer timer(m_inc_solver_timeout, &eh);
-                r = m_inc_solver->check_sat(0, 0);
-            }
-            if ((r != l_undef || !use_tactic_when_undef()) && !eh.m_canceled) {
-                m_use_inc_solver_results = true;
-                return r;
-            }
-        }
-        IF_VERBOSE(PS_VB_LVL, verbose_stream() << "incremental solver failed, trying tactic.\n";);                        
-    }
-    
-    m_use_inc_solver_results = false;
-    
-    if (factory == 0) {
-        IF_VERBOSE(PS_VB_LVL, verbose_stream() << "there is no tactic available for the current logic.\n";);            
-        m_reason_unknown         = "incomplete";
-        return l_undef; 
-    }
-
-    goal_ref g = alloc(goal, m(), m_produce_proofs, m_produce_models, m_produce_unsat_cores);
-    unsigned sz = get_num_assertions();
-    if (m_produce_unsat_cores) {
-        SASSERT(m_ctx->m_assertions.size() == m_ctx->m_assertion_names.size());
-        for (unsigned i = 0; i < sz; i++)
-            g->assert_expr(get_assertion(i), get_assertion_name(i));
-    }
-    else {
-        for (unsigned i = 0; i < sz; i++)
-            g->assert_expr(get_assertion(i));
-    }
-    expr_dependency_ref core(m());
-
-    TRACE("strategic_solver", tout << "using goal...\n"; g->display_with_dependencies(tout););
-    
-    mk_tactic tct_maker(this, factory, m_params);
-    SASSERT(m_curr_tactic);
-
-    proof_ref pr(m());
-    lbool r = ::check_sat(*(m_curr_tactic.get()), g, m_model, pr, core, m_reason_unknown);
-    m_curr_tactic->collect_statistics(m_stats);
-    if (pr) {
-        m_proof = pr; 
-        m().inc_ref(m_proof);
-    }
-    if (core) {
-        m_core = core;
-        m().inc_ref(m_core);
-    }
-    return r;
-}
-
-void strategic_solver::set_cancel(bool f) {
-    if (m_inc_solver)
-        m_inc_solver->set_cancel(f);
-    #pragma omp critical (strategic_solver)
-    {
-        if (m_curr_tactic)
-            m_curr_tactic->set_cancel(f);
-    }
-}
-
-void strategic_solver::get_unsat_core(ptr_vector<expr> & r) {
-    TRACE("strategic_solver", tout << "get_unsat_core, m_use_inc_solver_results: " << m_use_inc_solver_results << "\n";);
-    if (m_use_inc_solver_results) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->get_unsat_core(r); 
-    }
-    else {
-        m().linearize(m_core, r);
-    }
-}
-
-void strategic_solver::get_model(model_ref & m) {
-    if (m_use_inc_solver_results) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->get_model(m);
-    }
-    else {
-        m = m_model;
-    }
-}
-
-proof * strategic_solver::get_proof() {
-    if (m_use_inc_solver_results) {
-        SASSERT(m_inc_solver);
-        return m_inc_solver->get_proof();
-    }
-    else {
-        return m_proof;
-    }
-}
-
-std::string strategic_solver::reason_unknown() const {
-    if (m_use_inc_solver_results) {
-        SASSERT(m_inc_solver);
-        return m_inc_solver->reason_unknown();
-    }
-    return m_reason_unknown;
-}
-
-void strategic_solver::get_labels(svector<symbol> & r) {
-    if (m_use_inc_solver_results) {
-        SASSERT(m_inc_solver);
-        m_inc_solver->get_labels(r);
-    }
-}
-
-void strategic_solver::set_progress_callback(progress_callback * callback) { 
-    m_callback = callback; 
-    if (m_inc_solver)
-        m_inc_solver->set_progress_callback(callback);
-}
-
-void strategic_solver::display(std::ostream & out) const {
-    if (m_manager) {
-        unsigned num = get_num_assertions();
-        out << "(solver";
-        for (unsigned i = 0; i < num; i++) {
-            out << "\n  " << mk_ismt2_pp(get_assertion(i), m(), 2);
-        }
-        out << ")";
-    }
-    else {
-        out << "(solver)";
-    }
-}
-
-
-
-
-
-
diff --git a/src/solver/strategic_solver.h b/src/solver/strategic_solver.h
deleted file mode 100644
index 1883a88cd..000000000
--- a/src/solver/strategic_solver.h
+++ /dev/null
@@ -1,153 +0,0 @@
-/*++
-Copyright (c) 2011 Microsoft Corporation
-
-Module Name:
-
-    strategic_solver.h
-
-Abstract:
-
-    Strategies -> Solver
-
-Author:
-
-    Leonardo (leonardo) 2011-05-19
-
-Notes:
-
---*/
-#ifndef _STRATEGIC_SOLVER_H_
-#define _STRATEGIC_SOLVER_H_
-
-#include"solver.h"
-#include"tactic.h"
-
-class progress_callback;
-
-/**
-   \brief Implementation of the solver API that supports:
-       - a different tactic for each logic 
-       - a general purpose tactic
-       - a default incremental solver
-
-   The strategic solver has two modes:
-       - non-incremental
-       - incremental
-   In non-incremental mode, tactics are used.
-   In incremental model, the incremental (general purpose) solver is used.
-   
-   A timeout for the incremental solver can be specified.
-   If the timeout is reached, then the strategic_solver tries to solve the problem using tactics.
-
-   The strategic_solver switches to incremental when:
-       - push is used
-       - assertions are peformed after a check_sat
-   It goes back to non_incremental mode when:
-       - reset is invoked.
-*/
-class strategic_solver : public solver {
-public:
-    // Behavior when the incremental solver returns unknown.
-    enum inc_unknown_behavior {
-        IUB_RETURN_UNDEF,      // just return unknown
-        IUB_USE_TACTIC_IF_QF,  // invoke tactic if problem is quantifier free
-        IUB_USE_TACTIC         // invoke tactic
-    };
-
-private:
-    ast_manager *        m_manager;
-    params_ref           m_params;
-    symbol               m_logic;
-    bool                 m_force_tactic; // use tactics even when auto_config = false
-    bool                 m_inc_mode;
-    bool                 m_check_sat_executed;
-    scoped_ptr<solver>   m_inc_solver;
-    unsigned             m_inc_solver_timeout;
-    inc_unknown_behavior m_inc_unknown_behavior;
-    scoped_ptr<tactic_factory>  m_default_fct;
-    dictionary<tactic_factory*> m_logic2fct;
-
-    ref<tactic>          m_curr_tactic;
-    
-    bool                 m_use_inc_solver_results;
-    model_ref            m_model;
-    proof *              m_proof;
-    expr_dependency *    m_core;
-    std::string          m_reason_unknown;
-    statistics           m_stats;
-
-    struct ctx {
-        expr_ref_vector         m_assertions;
-        expr_ref_vector         m_assertion_names;
-        unsigned_vector         m_scopes;
-        ctx(ast_manager & m);
-    };
-    scoped_ptr<ctx>             m_ctx;
-
-#ifdef Z3DEBUG
-    unsigned             m_num_scopes;
-#endif
-
-    bool                 m_produce_proofs;
-    bool                 m_produce_models;
-    bool                 m_produce_unsat_cores;
-
-    bool                 m_auto_config;
-
-    progress_callback *  m_callback;
-
-    void reset_results();
-    void init_inc_solver();
-    tactic_factory * get_tactic_factory() const;
-    lbool check_sat_with_assumptions(unsigned num_assumptions, expr * const * assumptions);
-
-    struct mk_tactic;
-
-    bool has_quantifiers() const;
-    bool use_tactic_when_undef() const;
-
-public:
-    strategic_solver();
-    ~strategic_solver();
-
-    ast_manager & m() const { SASSERT(m_manager); return *m_manager; }
-
-    void set_inc_solver(solver * s);
-    void set_inc_solver_timeout(unsigned timeout);
-    void set_default_tactic(tactic_factory * fct);
-    void set_tactic_for(symbol const & logic, tactic_factory * fct);
-    void set_inc_unknown_behavior(inc_unknown_behavior b) { m_inc_unknown_behavior = b; }
-    void force_tactic(bool f) { m_force_tactic = f; }
-
-    virtual void updt_params(params_ref const & p);
-    virtual void collect_param_descrs(param_descrs & r);
-
-    virtual void set_produce_proofs(bool f);
-    virtual void set_produce_models(bool f);
-    virtual void set_produce_unsat_cores(bool f);
-
-    unsigned get_num_assertions() const;
-    expr * get_assertion(unsigned idx) const;
-    expr * get_assertion_name(unsigned idx) const;
-
-    virtual void display(std::ostream & out) const;
-    
-    virtual void init(ast_manager & m, symbol const & logic);
-    virtual void collect_statistics(statistics & st) const;
-    virtual void reset();
-    virtual void assert_expr(expr * t);
-    virtual void assert_expr(expr * t, expr * a);
-    virtual void push();
-    virtual void pop(unsigned n);
-    virtual unsigned get_scope_level() const;
-    virtual lbool check_sat(unsigned num_assumptions, expr * const * assumptions);
-    virtual void get_unsat_core(ptr_vector<expr> & r);
-    virtual void get_model(model_ref & m);
-    virtual proof * get_proof();
-    virtual std::string reason_unknown() const;
-    virtual void get_labels(svector<symbol> & r);
-    virtual void set_cancel(bool f);
-    virtual void set_progress_callback(progress_callback * callback);
-};
-
-#endif
diff --git a/src/solver/tactic2solver.cpp b/src/solver/tactic2solver.cpp
index e630f9c78..1268fbcea 100644
--- a/src/solver/tactic2solver.cpp
+++ b/src/solver/tactic2solver.cpp
@@ -19,96 +19,115 @@ Author:
 Notes:
 
 --*/
-#include"tactic2solver.h"
+#include"solver_na2as.h"
+#include"tactic.h"
 #include"ast_smt2_pp.h"
 
-tactic2solver_core::ctx::ctx(ast_manager & m, symbol const & logic):
-    m_logic(logic),
+/**
+   \brief Simulates the incremental solver interface using a tactic.
+
+   Every query will be solved from scratch.  So, this is not a good
+   option for applications trying to solve many easy queries that a
+   similar to each other.
+*/
+class tactic2solver : public solver_na2as {
+    expr_ref_vector              m_assertions;
+    unsigned_vector              m_scopes;
+    ref<simple_check_sat_result> m_result;
+    tactic_ref                   m_tactic;
+    symbol                       m_logic;
+    params_ref                   m_params;
+    bool                         m_produce_models;
+    bool                         m_produce_proofs;
+    bool                         m_produce_unsat_cores;
+public:
+    tactic2solver(ast_manager & m, tactic * t, params_ref const & p, bool produce_proofs, bool produce_models, bool produce_unsat_cores, symbol const & logic);
+    virtual ~tactic2solver();
+
+    virtual void updt_params(params_ref const & p);
+    virtual void collect_param_descrs(param_descrs & r);
+
+    virtual void set_produce_models(bool f) { m_produce_models = f; }
+
+    virtual void assert_expr(expr * t);
+
+    virtual void push_core();
+    virtual void pop_core(unsigned n);
+    virtual lbool check_sat_core(unsigned num_assumptions, expr * const * assumptions);
+
+    virtual void set_cancel(bool f);
+
+    virtual void collect_statistics(statistics & st) const;
+    virtual void get_unsat_core(ptr_vector<expr> & r);
+    virtual void get_model(model_ref & m);
+    virtual proof * get_proof();
+    virtual std::string reason_unknown() const;
+    virtual void get_labels(svector<symbol> & r) {}
+
+    virtual void set_progress_callback(progress_callback * callback) {}
+
+    virtual unsigned get_num_assertions() const;
+    virtual expr * get_assertion(unsigned idx) const;
+
+    virtual void display(std::ostream & out) const;
+};
+
+tactic2solver::tactic2solver(ast_manager & m, tactic * t, params_ref const & p, bool produce_proofs, bool produce_models, bool produce_unsat_cores, symbol const & logic):
+    solver_na2as(m),
     m_assertions(m) {
+
+    m_tactic = t;
+    m_logic  = logic;
+    m_params = p;
+    
+    m_produce_models      = produce_models;
+    m_produce_proofs      = produce_proofs;
+    m_produce_unsat_cores = produce_unsat_cores;
 }
 
-tactic2solver_core::~tactic2solver_core() {
+tactic2solver::~tactic2solver() {
 }
 
-void tactic2solver_core::init_core(ast_manager & m, symbol const & logic) {
-    m_ctx = alloc(ctx, m, logic);
-}
-
-void tactic2solver_core::updt_params(params_ref const & p) {
+void tactic2solver::updt_params(params_ref const & p) {
     m_params = p;
 }
 
-void tactic2solver_core::collect_param_descrs(param_descrs & r) {
-    if (m_ctx) {
-        if (!m_ctx->m_tactic) {
-            #pragma omp critical (tactic2solver_core)
-            {
-                m_ctx->m_tactic = get_tactic(m_ctx->m(), m_params);
-            }
-
-            if (m_ctx->m_tactic) {
-                m_ctx->m_tactic->collect_param_descrs(r);
-            }
-
-            #pragma omp critical (tactic2solver_core)
-            {
-                m_ctx->m_tactic = 0;
-            }
-        }
-        else {
-            m_ctx->m_tactic->collect_param_descrs(r);
-        }
-    }
+void tactic2solver::collect_param_descrs(param_descrs & r) {
+    if (m_tactic.get())
+        m_tactic->collect_param_descrs(r);
 }
 
-void tactic2solver_core::reset_core() {
-    SASSERT(m_ctx);
-    m_ctx->m_assertions.reset();
-    m_ctx->m_scopes.reset();
-    m_ctx->m_result = 0;
+void tactic2solver::assert_expr(expr * t) {
+    m_assertions.push_back(t);
+    m_result = 0;
 }
 
-void tactic2solver_core::assert_expr(expr * t) {
-    SASSERT(m_ctx);
-    m_ctx->m_assertions.push_back(t);
-    m_ctx->m_result = 0;
+void tactic2solver::push_core() {
+    m_scopes.push_back(m_assertions.size());
+    m_result = 0;
 }
 
-void tactic2solver_core::push_core() {
-    SASSERT(m_ctx);
-    m_ctx->m_scopes.push_back(m_ctx->m_assertions.size());
-    m_ctx->m_result = 0;
+void tactic2solver::pop_core(unsigned n) {
+    unsigned new_lvl = m_scopes.size() - n;
+    unsigned old_sz  = m_scopes[new_lvl];
+    m_assertions.shrink(old_sz);
+    m_scopes.shrink(new_lvl);
+    m_result = 0;
 }
 
-void tactic2solver_core::pop_core(unsigned n) {
-    SASSERT(m_ctx);
-    unsigned new_lvl = m_ctx->m_scopes.size() - n;
-    unsigned old_sz  = m_ctx->m_scopes[new_lvl];
-    m_ctx->m_assertions.shrink(old_sz);
-    m_ctx->m_scopes.shrink(new_lvl);
-    m_ctx->m_result = 0;
-}
-
-lbool tactic2solver_core::check_sat_core(unsigned num_assumptions, expr * const * assumptions) {
-    SASSERT(m_ctx);
-    ast_manager & m = m_ctx->m();
-    params_ref p = m_params;
-    #pragma omp critical (tactic2solver_core)
-    {
-        m_ctx->m_tactic = get_tactic(m, p);
-        if (m_ctx->m_tactic) {
-            m_ctx->m_result = alloc(simple_check_sat_result, m);
-        }
-    }
-    if (!m_ctx->m_tactic)
-        return l_undef;
-    tactic & t                       = *(m_ctx->m_tactic);
-    simple_check_sat_result & result = *(m_ctx->m_result);
+lbool tactic2solver::check_sat_core(unsigned num_assumptions, expr * const * assumptions) {
+    if (m_tactic.get() == 0)
+        return l_false;
+    ast_manager & m = m_assertions.m();
+    m_result = alloc(simple_check_sat_result, m);
+    m_tactic->cleanup();
+    m_tactic->updt_params(m_params);
+    m_tactic->set_logic(m_logic);
     goal_ref g = alloc(goal, m, m_produce_proofs, m_produce_models, m_produce_unsat_cores);
-    t.set_logic(m_ctx->m_logic);
-    unsigned sz = m_ctx->m_assertions.size();
+
+    unsigned sz = m_assertions.size();
     for (unsigned i = 0; i < sz; i++) {
-        g->assert_expr(m_ctx->m_assertions.get(i));
+        g->assert_expr(m_assertions.get(i));
     }
     for (unsigned i = 0; i < num_assumptions; i++) {
         g->assert_expr(assumptions[i], m.mk_asserted(assumptions[i]), m.mk_leaf(assumptions[i]));
@@ -119,17 +138,17 @@ lbool tactic2solver_core::check_sat_core(unsigned num_assumptions, expr * const
     expr_dependency_ref core(m);
     std::string         reason_unknown = "unknown";
     try {
-        switch (::check_sat(t, g, md, pr, core, reason_unknown)) {
+        switch (::check_sat(*m_tactic, g, md, pr, core, reason_unknown)) {
         case l_true: 
-            result.set_status(l_true);
+            m_result->set_status(l_true);
             break;
         case l_false: 
-            result.set_status(l_false);
+            m_result->set_status(l_false);
             break;
         default: 
-            result.set_status(l_undef);
+            m_result->set_status(l_undef);
             if (reason_unknown != "")
-                result.m_unknown = reason_unknown;
+                m_result->m_unknown = reason_unknown;
             break;
         }
     }
@@ -137,112 +156,115 @@ lbool tactic2solver_core::check_sat_core(unsigned num_assumptions, expr * const
         throw ex;
     }
     catch (z3_exception & ex) {
-        TRACE("tactic2solver_core", tout << "exception: " << ex.msg() << "\n";);
-        result.set_status(l_undef);
-        result.m_unknown = ex.msg();
+        TRACE("tactic2solver", tout << "exception: " << ex.msg() << "\n";);
+        m_result->set_status(l_undef);
+        m_result->m_unknown = ex.msg();
     }
-    t.collect_statistics(result.m_stats);
-    result.m_model = md;
-    result.m_proof = pr;
+    m_tactic->collect_statistics(m_result->m_stats);
+    m_result->m_model = md;
+    m_result->m_proof = pr;
     if (m_produce_unsat_cores) {
         ptr_vector<expr> core_elems;
         m.linearize(core, core_elems);
-        result.m_core.append(core_elems.size(), core_elems.c_ptr());
+        m_result->m_core.append(core_elems.size(), core_elems.c_ptr());
     }
-    
-    #pragma omp critical (tactic2solver_core)
-    {
-        m_ctx->m_tactic = 0;
-    }
-    return result.status();
+    m_tactic->cleanup();
+    return m_result->status();
 }
 
-void tactic2solver_core::set_cancel(bool f) {
-    #pragma omp critical (tactic2solver_core)
-    {
-        if (m_ctx && m_ctx->m_tactic)
-            m_ctx->m_tactic->set_cancel(f);
-    }
+void tactic2solver::set_cancel(bool f) {
+    if (m_tactic.get())
+        m_tactic->set_cancel(f);
 }
 
-void tactic2solver_core::collect_statistics(statistics & st) const {
-    if (m_ctx->m_result.get())
-        m_ctx->m_result->collect_statistics(st);
+void tactic2solver::collect_statistics(statistics & st) const {
+    if (m_result.get())
+        m_result->collect_statistics(st);
 }
 
-void tactic2solver_core::get_unsat_core(ptr_vector<expr> & r) {
-    if (m_ctx->m_result.get())
-        m_ctx->m_result->get_unsat_core(r);
+void tactic2solver::get_unsat_core(ptr_vector<expr> & r) {
+    if (m_result.get())
+        m_result->get_unsat_core(r);
 }
 
-void tactic2solver_core::get_model(model_ref & m) {
-    if (m_ctx->m_result.get())
-        m_ctx->m_result->get_model(m);
+void tactic2solver::get_model(model_ref & m) {
+    if (m_result.get())
+        m_result->get_model(m);
 }
 
-proof * tactic2solver_core::get_proof() {
-    if (m_ctx->m_result.get())
-        return m_ctx->m_result->get_proof();
+proof * tactic2solver::get_proof() {
+    if (m_result.get())
+        return m_result->get_proof();
     else
         return 0;
 }
 
-std::string tactic2solver_core::reason_unknown() const {
-    if (m_ctx->m_result.get())
-        return m_ctx->m_result->reason_unknown();
+std::string tactic2solver::reason_unknown() const {
+    if (m_result.get())
+        return m_result->reason_unknown();
     else
         return std::string("unknown");
 }
 
-unsigned tactic2solver_core::get_num_assertions() const {
-    if (m_ctx) 
-        return m_ctx->m_assertions.size();
-    else
-        return 0;
+unsigned tactic2solver::get_num_assertions() const {
+    return m_assertions.size();
 }
 
-expr * tactic2solver_core::get_assertion(unsigned idx) const {
-    SASSERT(m_ctx);
-    return m_ctx->m_assertions.get(idx);
+expr * tactic2solver::get_assertion(unsigned idx) const {
+    return m_assertions.get(idx);
 }
 
-void tactic2solver_core::display(std::ostream & out) const {
-    if (m_ctx) {
-        ast_manager & m = m_ctx->m_assertions.m();
-        unsigned num = m_ctx->m_assertions.size();
-        out << "(solver";
-        for (unsigned i = 0; i < num; i++) {
-            out << "\n  " << mk_ismt2_pp(m_ctx->m_assertions.get(i), m, 2);
-        }
-        out << ")";
+void tactic2solver::display(std::ostream & out) const {
+    ast_manager & m = m_assertions.m();
+    unsigned num = m_assertions.size();
+    out << "(solver";
+    for (unsigned i = 0; i < num; i++) {
+        out << "\n  " << mk_ismt2_pp(m_assertions.get(i), m, 2);
     }
-    else {
-        out << "(solver)";
+    out << ")";
+}
+
+solver * mk_tactic2solver(ast_manager & m, 
+                          tactic * t, 
+                          params_ref const & p,
+                          bool produce_proofs,
+                          bool produce_models,
+                          bool produce_unsat_cores,
+                          symbol const & logic) {
+    return alloc(tactic2solver, m, t, p, produce_proofs, produce_models, produce_unsat_cores, logic);
+}
+
+class tactic2solver_factory : public solver_factory {
+    ref<tactic> m_tactic;
+public:
+    tactic2solver_factory(tactic * t):m_tactic(t) {
     }
+    
+    virtual ~tactic2solver_factory() {}
+    
+    virtual solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) {
+        return mk_tactic2solver(m, m_tactic.get(), p, proofs_enabled, models_enabled, unsat_core_enabled, logic);
+    }
+};
+
+class tactic_factory2solver_factory : public solver_factory {
+    scoped_ptr<tactic_factory> m_factory;
+public:
+    tactic_factory2solver_factory(tactic_factory * f):m_factory(f) {
+    }
+    
+    virtual ~tactic_factory2solver_factory() {}
+    
+    virtual solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) {
+        tactic * t = (*m_factory)(m, p);
+        return mk_tactic2solver(m, t, p, proofs_enabled, models_enabled, unsat_core_enabled, logic);
+    }
+};
+
+solver_factory * mk_tactic2solver_factory(tactic * t) {
+    return alloc(tactic2solver_factory, t);
 }
 
-tactic2solver::tactic2solver(tactic * t):
-    m_tactic(t) {
-}
-
-tactic2solver::~tactic2solver() {
-}
-
-tactic * tactic2solver::get_tactic(ast_manager & m, params_ref const & p) {
-    m_tactic->cleanup();
-    m_tactic->updt_params(p);
-    return m_tactic.get();
-}
-
-tactic_factory2solver::~tactic_factory2solver() {
-}
-
-void tactic_factory2solver::set_tactic(tactic_factory * f) {
-    m_tactic_factory = f;
-}
-
-tactic * tactic_factory2solver::get_tactic(ast_manager & m, params_ref const & p) {
-    if (m_tactic_factory == 0)
-        return 0;
-    return (*m_tactic_factory)(m, p);
+solver_factory * mk_tactic_factory2solver_factory(tactic_factory * f) {
+    return alloc(tactic_factory2solver_factory, f);
 }
diff --git a/src/solver/tactic2solver.h b/src/solver/tactic2solver.h
index 0a057b04b..f20b1c4dd 100644
--- a/src/solver/tactic2solver.h
+++ b/src/solver/tactic2solver.h
@@ -22,88 +22,22 @@ Notes:
 #ifndef _TACTIC2SOLVER_H_
 #define _TACTIC2SOLVER_H_
 
-#include"solver_na2as.h"
-#include"tactic.h"
+#include"params.h"
+class ast_manager;
+class tactic;
+class tactic_factory;
+class solver;
+class solver_factory;
 
-/**
-   \brief Simulates the incremental solver interface using a tactic.
-
-   Every query will be solved from scratch.  So, this is not a good
-   option for applications trying to solve many easy queries that a
-   similar to each other.
-*/
-class tactic2solver_core : public solver_na2as {
-    struct ctx {
-        symbol                       m_logic;
-        expr_ref_vector              m_assertions;
-        unsigned_vector              m_scopes;
-        ref<simple_check_sat_result> m_result;
-        tactic_ref                   m_tactic;
-        ctx(ast_manager & m, symbol const & logic);
-        ast_manager & m() const { return m_assertions.m(); }
-    };
-    scoped_ptr<ctx>            m_ctx;
-    params_ref                 m_params;
-    bool                       m_produce_models;
-    bool                       m_produce_proofs;
-    bool                       m_produce_unsat_cores;
-public:
-    tactic2solver_core():m_ctx(0), m_produce_models(false), m_produce_proofs(false), m_produce_unsat_cores(false) {}
-    virtual ~tactic2solver_core();
-
-    virtual tactic * get_tactic(ast_manager & m, params_ref const & p) = 0;
-    
-    virtual void updt_params(params_ref const & p);
-    virtual void collect_param_descrs(param_descrs & r);
-
-    virtual void set_produce_proofs(bool f) { m_produce_proofs = f; }
-    virtual void set_produce_models(bool f) { m_produce_models = f; }
-    virtual void set_produce_unsat_cores(bool f) { m_produce_unsat_cores = f; }
-
-    virtual void assert_expr(expr * t);
-
-    virtual void init_core(ast_manager & m, symbol const & logic);
-    virtual void reset_core();
-    virtual void push_core();
-    virtual void pop_core(unsigned n);
-    virtual lbool check_sat_core(unsigned num_assumptions, expr * const * assumptions);
-
-    virtual void set_cancel(bool f);
-
-    virtual void collect_statistics(statistics & st) const;
-    virtual void get_unsat_core(ptr_vector<expr> & r);
-    virtual void get_model(model_ref & m);
-    virtual proof * get_proof();
-    virtual std::string reason_unknown() const;
-    virtual void get_labels(svector<symbol> & r) {}
-
-    virtual void set_progress_callback(progress_callback * callback) {}
-
-    virtual unsigned get_num_assertions() const;
-    virtual expr * get_assertion(unsigned idx) const;
-
-    virtual void display(std::ostream & out) const;
-};
-
-class tactic2solver : public tactic2solver_core {
-    tactic_ref m_tactic;
-public:
-    tactic2solver(tactic * t);
-    virtual ~tactic2solver();
-    virtual tactic * get_tactic(ast_manager & m, params_ref const & p);
-};
-
-
-class tactic_factory2solver : public tactic2solver_core {
-    scoped_ptr<tactic_factory> m_tactic_factory;
-public:
-    virtual ~tactic_factory2solver();
-    /**
-       \brief Set tactic that will be used to process the satisfiability queries.
-    */
-    void set_tactic(tactic_factory * f); 
-    virtual tactic * get_tactic(ast_manager & m, params_ref const & p);
-};
+solver * mk_tactic2solver(ast_manager & m, 
+                          tactic * t = 0, 
+                          params_ref const & p = params_ref(), 
+                          bool produce_proofs = false, 
+                          bool produce_models = true, 
+                          bool produce_unsat_cores = false, 
+                          symbol const & logic = symbol::null);
 
+solver_factory * mk_tactic2solver_factory(tactic * t);
+solver_factory * mk_tactic_factory2solver_factory(tactic_factory * f);
 
 #endif
diff --git a/src/tactic/arith/bv2int_rewriter.cpp b/src/tactic/arith/bv2int_rewriter.cpp
index 0965f36f2..872981283 100644
--- a/src/tactic/arith/bv2int_rewriter.cpp
+++ b/src/tactic/arith/bv2int_rewriter.cpp
@@ -544,7 +544,7 @@ bool bv2int_rewriter::is_sbv2int(expr* n, expr_ref& s) {
         m_bv.is_extract(e2, lo1, hi1, e3) &&
         lo1 == 0 && hi1 == hi-1 &&
         m_arith.is_numeral(t2, k, is_int) && is_int &&
-        k == m_bv.power_of_two(hi) 
+        k == rational::power_of_two(hi) 
         ) {
         s = e3;
         return true;
diff --git a/src/tactic/arith/nla2bv_tactic.cpp b/src/tactic/arith/nla2bv_tactic.cpp
index 188ea7d70..bd5af58f2 100644
--- a/src/tactic/arith/nla2bv_tactic.cpp
+++ b/src/tactic/arith/nla2bv_tactic.cpp
@@ -253,7 +253,7 @@ class nla2bv_tactic : public tactic {
                 s_bv = m_arith.mk_sub(m_arith.mk_numeral(*up, true), s_bv);
             }
             else {
-                s_bv = m_arith.mk_sub(s_bv, m_arith.mk_numeral(m_bv.power_of_two(num_bits-1), true));
+                s_bv = m_arith.mk_sub(s_bv, m_arith.mk_numeral(rational::power_of_two(num_bits-1), true));
             }
             
             m_trail.push_back(s_bv);
diff --git a/src/tactic/arith/pb2bv_tactic.cpp b/src/tactic/arith/pb2bv_tactic.cpp
index 8790ca5a7..83a949579 100644
--- a/src/tactic/arith/pb2bv_tactic.cpp
+++ b/src/tactic/arith/pb2bv_tactic.cpp
@@ -583,7 +583,7 @@ private:
                 return false; // size must be even
             // I implemented only the easy (and very common) case, where a_i = 2^{n-i-1} and c = 2^n - 1
             unsigned n = sz/2;
-            if (c != m_bv_util.power_of_two(n) - numeral(1))
+            if (c != rational::power_of_two(n) - numeral(1))
                 return false;
             for (unsigned i = 0; i < n; i++) {
                 monomial const & m1 = p[i*2];
@@ -592,7 +592,7 @@ private:
                     return false;
                 if (m1.m_a != m2.m_a)
                     return false;
-                if (m1.m_a != m_bv_util.power_of_two(n - i - 1))
+                if (m1.m_a != rational::power_of_two(n - i - 1))
                     return false;
             }
             return true;
diff --git a/src/tactic/core/ctx_simplify_tactic.cpp b/src/tactic/core/ctx_simplify_tactic.cpp
index cca21b90e..831efa087 100644
--- a/src/tactic/core/ctx_simplify_tactic.cpp
+++ b/src/tactic/core/ctx_simplify_tactic.cpp
@@ -18,7 +18,7 @@ Notes:
 --*/
 #include"ctx_simplify_tactic.h"
 #include"mk_simplified_app.h"
-#include"num_occurs_goal.h"
+#include"goal_num_occurs.h"
 #include"cooperate.h"
 #include"ast_ll_pp.h"
 #include"ast_smt2_pp.h"
@@ -51,7 +51,7 @@ struct ctx_simplify_tactic::imp {
     unsigned                    m_scope_lvl;
     unsigned                    m_depth;                  
     unsigned                    m_num_steps;
-    num_occurs_goal             m_occs;
+    goal_num_occurs             m_occs;
     mk_simplified_app           m_mk_app;
     unsigned long long          m_max_memory;
     unsigned                    m_max_depth;
diff --git a/src/tactic/core/elim_uncnstr_tactic.cpp b/src/tactic/core/elim_uncnstr_tactic.cpp
index d1dca296a..00e14a41f 100644
--- a/src/tactic/core/elim_uncnstr_tactic.cpp
+++ b/src/tactic/core/elim_uncnstr_tactic.cpp
@@ -647,9 +647,9 @@ class elim_uncnstr_tactic : public tactic {
                     unsigned bv_sz = m_bv_util.get_bv_size(arg1);
                     rational MAX;
                     if (is_signed)
-                        MAX = m_bv_util.power_of_two(bv_sz - 1) - rational(1);
+                        MAX = rational::power_of_two(bv_sz - 1) - rational(1);
                     else
-                        MAX = m_bv_util.power_of_two(bv_sz) - rational(1);
+                        MAX = rational::power_of_two(bv_sz) - rational(1);
                     app * u;
                     bool is_new = mk_fresh_uncnstr_var_for(f, arg1, arg2, u);
                     app * r = m().mk_or(u, m().mk_eq(t, m_bv_util.mk_numeral(MAX, bv_sz)));
@@ -666,7 +666,7 @@ class elim_uncnstr_tactic : public tactic {
                     unsigned bv_sz = m_bv_util.get_bv_size(arg1);
                     rational MIN;
                     if (is_signed)
-                        MIN = -m_bv_util.power_of_two(bv_sz - 1);
+                        MIN = -rational::power_of_two(bv_sz - 1);
                     else
                         MIN = rational(0);
                     app * u;
diff --git a/src/tactic/core/nnf_tactic.cpp b/src/tactic/core/nnf_tactic.cpp
index a79a4ed06..19190c299 100644
--- a/src/tactic/core/nnf_tactic.cpp
+++ b/src/tactic/core/nnf_tactic.cpp
@@ -18,6 +18,7 @@ Revision History:
 --*/
 #include"nnf.h"
 #include"tactical.h"
+#include"filter_model_converter.h"
 
 class nnf_tactic : public tactic {
     params_ref    m_params;
@@ -100,6 +101,13 @@ public:
         }
         g->inc_depth();
         result.push_back(g.get());
+        unsigned num_extra_names = dnames.get_num_names();
+        if (num_extra_names > 0) {
+            filter_model_converter * fmc = alloc(filter_model_converter, m);
+            mc = fmc;
+            for (unsigned i = 0; i < num_extra_names; i++)
+                fmc->insert(dnames.get_name_decl(i));
+        }
         TRACE("nnf", g->display(tout););
         SASSERT(g->is_well_sorted());
     }
diff --git a/src/tactic/fpa/fpa2bv_converter.cpp b/src/tactic/fpa/fpa2bv_converter.cpp
index 8a4b31612..b53ad21eb 100644
--- a/src/tactic/fpa/fpa2bv_converter.cpp
+++ b/src/tactic/fpa/fpa2bv_converter.cpp
@@ -32,7 +32,7 @@ fpa2bv_converter::fpa2bv_converter(ast_manager & m) :
 	m_mpz_manager(m_mpf_manager.mpz_manager()),
     m_bv_util(m),
     extra_assertions(m) {
-    m_plugin = static_cast<float_decl_plugin*>(m.get_plugin(m.get_family_id("float")));
+    m_plugin = static_cast<float_decl_plugin*>(m.get_plugin(m.mk_family_id("float")));
 }
 
 fpa2bv_converter::~fpa2bv_converter() {
diff --git a/src/tactic/num_occurs_goal.cpp b/src/tactic/goal_num_occurs.cpp
similarity index 75%
rename from src/tactic/num_occurs_goal.cpp
rename to src/tactic/goal_num_occurs.cpp
index adc412434..6c94e307c 100644
--- a/src/tactic/num_occurs_goal.cpp
+++ b/src/tactic/goal_num_occurs.cpp
@@ -3,7 +3,7 @@ Copyright (c) 2012 Microsoft Corporation
 
 Module Name:
 
-    num_occurs_goal.cpp
+    goal_num_occurs.cpp
 
 Abstract:
 
@@ -15,10 +15,10 @@ Author:
 Revision History:
 
 --*/
-#include"num_occurs_goal.h"
+#include"goal_num_occurs.h"
 #include"goal.h"
 
-void num_occurs_goal::operator()(goal const & g) {
+void goal_num_occurs::operator()(goal const & g) {
     expr_fast_mark1   visited;
     unsigned sz = g.size();
     for (unsigned i = 0; i < sz; i++) {
diff --git a/src/tactic/num_occurs_goal.h b/src/tactic/goal_num_occurs.h
similarity index 64%
rename from src/tactic/num_occurs_goal.h
rename to src/tactic/goal_num_occurs.h
index 5e6e0cc94..33a25e03f 100644
--- a/src/tactic/num_occurs_goal.h
+++ b/src/tactic/goal_num_occurs.h
@@ -3,7 +3,7 @@ Copyright (c) 2012 Microsoft Corporation
 
 Module Name:
 
-    num_occurs_goal.h
+    goal_num_occurs.h
 
 Abstract:
 
@@ -15,16 +15,16 @@ Author:
 Revision History:
 
 --*/
-#ifndef _NUM_OCCURS_GOAL_H_
-#define _NUM_OCCURS_GOAL_H_
+#ifndef _GOAL_NUM_OCCURS_H_
+#define _GOAL_NUM_OCCURS_H_
 
 #include"num_occurs.h"
 
 class goal;
 
-class num_occurs_goal : public num_occurs { 
+class goal_num_occurs : public num_occurs { 
 public:
-    num_occurs_goal(bool ignore_ref_count1 = false, bool ignore_quantifiers = false):
+    goal_num_occurs(bool ignore_ref_count1 = false, bool ignore_quantifiers = false):
         num_occurs(ignore_ref_count1, ignore_quantifiers) {
     }
 
diff --git a/src/tactic/portfolio/smt_strategic_solver.cpp b/src/tactic/portfolio/smt_strategic_solver.cpp
index 7a274a830..0e63255ca 100644
--- a/src/tactic/portfolio/smt_strategic_solver.cpp
+++ b/src/tactic/portfolio/smt_strategic_solver.cpp
@@ -18,7 +18,8 @@ Notes:
 
 --*/
 #include"cmd_context.h"
-#include"strategic_solver.h"
+#include"combined_solver.h"
+#include"tactic2solver.h"
 #include"qfbv_tactic.h"
 #include"qflia_tactic.h"
 #include"qfnia_tactic.h"
@@ -36,57 +37,76 @@ Notes:
 #include"horn_tactic.h"
 #include"smt_solver.h"
 
-MK_SIMPLE_TACTIC_FACTORY(qfuf_fct, mk_qfuf_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfidl_fct, mk_qfidl_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfauflia_fct, mk_qfauflia_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(auflia_fct, mk_auflia_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(auflira_fct, mk_auflira_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(aufnira_fct, mk_aufnira_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(ufnia_fct, mk_ufnia_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(uflra_fct, mk_uflra_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(lra_fct, mk_lra_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfbv_fct, mk_qfbv_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(default_fct, mk_default_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfaufbv_fct, mk_qfaufbv_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qflra_fct, mk_qflra_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qflia_fct, mk_qflia_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfufbv_fct, mk_qfufbv_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfnia_fct, mk_qfnia_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qfnra_fct, mk_qfnra_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(qffpa_fct, mk_qffpa_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(ufbv_fct, mk_ufbv_tactic(m, p));
-MK_SIMPLE_TACTIC_FACTORY(horn_fct, mk_horn_tactic(m, p));
-
-static void init(strategic_solver * s) {
-    s->set_default_tactic(alloc(default_fct));
-    s->set_tactic_for(symbol("QF_UF"),     alloc(qfuf_fct));
-    s->set_tactic_for(symbol("QF_BV"),     alloc(qfbv_fct));
-    s->set_tactic_for(symbol("QF_IDL"),    alloc(qfidl_fct));
-    s->set_tactic_for(symbol("QF_LIA"),    alloc(qflia_fct));
-    s->set_tactic_for(symbol("QF_LRA"),    alloc(qflra_fct));
-    s->set_tactic_for(symbol("QF_NIA"),    alloc(qfnia_fct));
-    s->set_tactic_for(symbol("QF_NRA"),    alloc(qfnra_fct));
-    s->set_tactic_for(symbol("QF_AUFLIA"), alloc(qfauflia_fct));
-    s->set_tactic_for(symbol("QF_AUFBV"),  alloc(qfaufbv_fct));
-    s->set_tactic_for(symbol("QF_ABV"),    alloc(qfaufbv_fct));
-    s->set_tactic_for(symbol("QF_UFBV"),   alloc(qfufbv_fct));
-    s->set_tactic_for(symbol("AUFLIA"),    alloc(auflia_fct));
-    s->set_tactic_for(symbol("AUFLIRA"),   alloc(auflira_fct));
-    s->set_tactic_for(symbol("AUFNIRA"),   alloc(aufnira_fct));
-    s->set_tactic_for(symbol("UFNIA"),     alloc(ufnia_fct));
-    s->set_tactic_for(symbol("UFLRA"),     alloc(uflra_fct));
-    s->set_tactic_for(symbol("LRA"),       alloc(lra_fct));
-    s->set_tactic_for(symbol("UFBV"),      alloc(ufbv_fct));
-    s->set_tactic_for(symbol("BV"),        alloc(ufbv_fct));        
-    s->set_tactic_for(symbol("QF_FPA"),    alloc(qffpa_fct));
-    s->set_tactic_for(symbol("QF_FPABV"),    alloc(qffpa_fct));
-    s->set_tactic_for(symbol("HORN"),      alloc(horn_fct));
+tactic * mk_tactic_for_logic(ast_manager & m, params_ref const & p, symbol const & logic) {
+    if (logic=="QF_UF")
+        return mk_qfuf_tactic(m, p);
+    else if (logic=="QF_BV")
+        return mk_qfbv_tactic(m, p);
+    else if (logic=="QF_IDL")
+        return mk_qfidl_tactic(m, p);
+    else if (logic=="QF_LIA")
+        return mk_qflia_tactic(m, p);
+    else if (logic=="QF_LRA")
+        return mk_qflra_tactic(m, p);
+    else if (logic=="QF_NIA")
+        return mk_qfnia_tactic(m, p);
+    else if (logic=="QF_NRA")
+        return mk_qfnra_tactic(m, p);
+    else if (logic=="QF_AUFLIA")
+        return mk_qfauflia_tactic(m, p);
+    else if (logic=="QF_AUFBV")
+        return mk_qfaufbv_tactic(m, p);
+    else if (logic=="QF_ABV")
+        return mk_qfaufbv_tactic(m, p);
+    else if (logic=="QF_UFBV")
+        return mk_qfufbv_tactic(m, p);
+    else if (logic=="AUFLIA")
+        return mk_auflia_tactic(m, p);
+    else if (logic=="AUFLIRA")
+        return mk_auflira_tactic(m, p);
+    else if (logic=="AUFNIRA")
+        return mk_aufnira_tactic(m, p);
+    else if (logic=="UFNIA")
+        return mk_ufnia_tactic(m, p);
+    else if (logic=="UFLRA")
+        return mk_uflra_tactic(m, p);
+    else if (logic=="LRA")
+        return mk_lra_tactic(m, p);
+    else if (logic=="UFBV")
+        return mk_ufbv_tactic(m, p);
+    else if (logic=="BV")
+        return mk_ufbv_tactic(m, p);
+    else if (logic=="QF_FPA")
+        return mk_qffpa_tactic(m, p);
+    else if (logic=="QF_FPABV")
+        return mk_qffpa_tactic(m, p);
+    else if (logic=="HORN")
+        return mk_horn_tactic(m, p);
+    else 
+        return mk_default_tactic(m, p);
 }
 
-solver * mk_smt_strategic_solver(bool force_tactic) {
-    strategic_solver * s = alloc(strategic_solver);
-    s->force_tactic(force_tactic);
-    s->set_inc_solver(mk_smt_solver());
-    init(s);
-    return s;
+class smt_strategic_solver_factory : public solver_factory {
+    symbol m_logic;
+public:
+    smt_strategic_solver_factory(symbol const & logic):m_logic(logic) {}
+    
+    virtual ~smt_strategic_solver_factory() {}
+    
+    virtual solver * operator()(ast_manager & m, params_ref const & p, bool proofs_enabled, bool models_enabled, bool unsat_core_enabled, symbol const & logic) {
+        symbol l;
+        if (m_logic != symbol::null)
+            l = m_logic;
+        else
+            l = logic;
+        tactic * t = mk_tactic_for_logic(m, p, l);
+        return mk_combined_solver(mk_tactic2solver(m, t, p, proofs_enabled, models_enabled, unsat_core_enabled, l),
+                                  mk_smt_solver(m, p, l),
+                                  p);
+    }
+};
+
+solver_factory * mk_smt_strategic_solver_factory(symbol const & logic) {
+    return alloc(smt_strategic_solver_factory, logic);
 }
+
diff --git a/src/tactic/portfolio/smt_strategic_solver.h b/src/tactic/portfolio/smt_strategic_solver.h
index 060721e09..1d132532a 100644
--- a/src/tactic/portfolio/smt_strategic_solver.h
+++ b/src/tactic/portfolio/smt_strategic_solver.h
@@ -20,8 +20,8 @@ Notes:
 #ifndef _SMT_STRATEGIC_SOLVER_H_
 #define _SMT_STRATEGIC_SOLVER_H_
 
-class solver;
-// Create a strategic solver for the Z3 API
-solver * mk_smt_strategic_solver(bool force_tactic=false);
+class solver_factory;
+
+solver_factory * mk_smt_strategic_solver_factory(symbol const & logic = symbol::null);
 
 #endif
diff --git a/src/tactic/probe.cpp b/src/tactic/probe.cpp
index 2940e93b9..1a696dc78 100644
--- a/src/tactic/probe.cpp
+++ b/src/tactic/probe.cpp
@@ -326,7 +326,7 @@ class num_consts_probe : public probe {
         unsigned      m_counter;
         proc(ast_manager & _m, bool b, char const * family):m(_m), m_bool(b), m_counter(0) {
             if (family != 0)
-                m_fid = m.get_family_id(family);
+                m_fid = m.mk_family_id(family);
             else
                 m_fid = null_family_id;
         }
diff --git a/src/tactic/smtlogics/qflia_tactic.cpp b/src/tactic/smtlogics/qflia_tactic.cpp
index 6b05cff96..6fbf34255 100644
--- a/src/tactic/smtlogics/qflia_tactic.cpp
+++ b/src/tactic/smtlogics/qflia_tactic.cpp
@@ -172,6 +172,8 @@ tactic * mk_qflia_tactic(ast_manager & m, params_ref const & p) {
     params_ref main_p;
     main_p.set_bool("elim_and", true);
     main_p.set_bool("som", true);
+    main_p.set_bool("blast_distinct", true);
+    main_p.set_uint("blast_distinct_threshold", 128);
     // main_p.set_bool("push_ite_arith", true);
     
     params_ref pull_ite_p;
diff --git a/src/tactic/tactic.cpp b/src/tactic/tactic.cpp
index 4bf9e48f4..198872cf5 100644
--- a/src/tactic/tactic.cpp
+++ b/src/tactic/tactic.cpp
@@ -175,7 +175,6 @@ tactic * mk_fail_if_undecided_tactic() {
 
 void exec(tactic & t, goal_ref const & in, goal_ref_buffer & result, model_converter_ref & mc, proof_converter_ref & pc, expr_dependency_ref & core) {
     t.reset_statistics();
-    t.reset_cancel();
     try {
         t(in, result, mc, pc, core);
         t.cleanup();
diff --git a/src/tactic/tactical.cpp b/src/tactic/tactical.cpp
index 785a9d82e..ca66b7a14 100644
--- a/src/tactic/tactical.cpp
+++ b/src/tactic/tactical.cpp
@@ -116,7 +116,6 @@ protected:
         m_t2->set_cancel(f);
     }
 
-
     template<typename T>
     tactic * translate_core(ast_manager & m) { 
         tactic * new_t1 = m_t1->translate(m);
diff --git a/src/test/bv_simplifier_plugin.cpp b/src/test/bv_simplifier_plugin.cpp
index 4a472425e..635143021 100644
--- a/src/test/bv_simplifier_plugin.cpp
+++ b/src/test/bv_simplifier_plugin.cpp
@@ -79,7 +79,7 @@ public:
         m_arith(m_manager),
         m_simp(m_manager, m_bsimp, m_bv_params), 
         m_bv_util(m_manager), 
-        m_fid(m_manager.get_family_id("bv")) {
+        m_fid(m_manager.mk_family_id("bv")) {
         reg_decl_plugins(m_manager);
     }
 
@@ -139,7 +139,7 @@ public:
         m_simp.reduce(ar->get_decl(), ar->get_num_args(), ar->get_args(), e);
         SASSERT(((a >> 8) | (a << 24)) == u32(e.get()));
 
-        params[0] = parameter(m_manager.mk_sort(m_manager.get_family_id("arith"), INT_SORT));
+        params[0] = parameter(m_manager.mk_sort(m_manager.mk_family_id("arith"), INT_SORT));
         ar = m_manager.mk_app(m_fid, OP_BV2INT, 1, params, 1, es);
 		expr* es2[1] = { ar.get() };
 		params[0] = parameter(32);
diff --git a/src/test/expr_rand.cpp b/src/test/expr_rand.cpp
index 1ceeba8b8..19a07e98a 100644
--- a/src/test/expr_rand.cpp
+++ b/src/test/expr_rand.cpp
@@ -18,7 +18,7 @@ void tst_expr_arith(unsigned num_files) {
     er.seed(rand_seed);
     er.initialize_arith(20);
 
-    family_id fid = m.get_family_id("arith");
+    family_id fid = m.mk_family_id("arith");
     sort* int_ty  = m.mk_sort(fid, INT_SORT, 0, 0);
     sort* real_ty = m.mk_sort(fid, REAL_SORT, 0, 0);
 
@@ -56,7 +56,7 @@ void tst_expr_rand(unsigned num_files) {
     parameter p2(2);
     parameter p8(8);
     parameter p32(32);
-    family_id bvfid = m.get_family_id("bv");
+    family_id bvfid = m.mk_family_id("bv");
     sort* bv1  = m.mk_sort(bvfid, BV_SORT, 1, &p1);
     sort* bv2  = m.mk_sort(bvfid, BV_SORT, 1, &p2);
     sort* bv8  = m.mk_sort(bvfid, BV_SORT, 1, &p8);
diff --git a/src/test/fuzzing/expr_rand.cpp b/src/test/fuzzing/expr_rand.cpp
index e1a7631c4..a2aca7e6e 100644
--- a/src/test/fuzzing/expr_rand.cpp
+++ b/src/test/fuzzing/expr_rand.cpp
@@ -82,7 +82,7 @@ expr* expr_rand::choose_expr(sort* s) {
 
 void expr_rand::initialize_arith(unsigned num_vars) {
     arith_util u(m_manager);
-    family_id afid = m_manager.get_family_id("arith");
+    family_id afid = m_manager.mk_family_id("arith");
     sort* i_ty = m_manager.mk_sort(afid, INT_SORT, 0, 0);
     for(unsigned i = 0; i < num_vars; ++i) {
         add_var(i_ty);
@@ -106,7 +106,7 @@ void expr_rand::initialize_arith(unsigned num_vars) {
 void expr_rand::initialize_bv(unsigned num_vars) {
     bv_util u(m_manager);
     family_id bfid = m_manager.get_basic_family_id();
-    family_id bvfid = m_manager.get_family_id("bv");
+    family_id bvfid = m_manager.mk_family_id("bv");
     
 
     const unsigned num_sizes = 6;
@@ -237,7 +237,7 @@ void expr_rand::initialize_bv(unsigned num_vars) {
 }
 
 void expr_rand::initialize_array(unsigned num_vars, sort* dom, sort* rng) {
-    family_id afid = m_manager.get_family_id("array");
+    family_id afid = m_manager.mk_family_id("array");
     parameter p1(dom), p2(rng);
     parameter ps[2] = { p1, p2 };
     sort* a = m_manager.mk_sort(afid, ARRAY_SORT, 2, ps);
diff --git a/src/test/get_implied_equalities.cpp b/src/test/get_implied_equalities.cpp
index 91c71438f..2576920cc 100644
--- a/src/test/get_implied_equalities.cpp
+++ b/src/test/get_implied_equalities.cpp
@@ -3,11 +3,11 @@
 #include "debug.h"
 
 static Z3_ast mk_var(Z3_context ctx, char const* name, Z3_sort s) {
-	return Z3_mk_const(ctx, Z3_mk_string_symbol(ctx, name), s);
+    return Z3_mk_const(ctx, Z3_mk_string_symbol(ctx, name), s);
 }
 
 static Z3_ast mk_int_var(Z3_context ctx, char const* name) {
-	return mk_var(ctx, name, Z3_mk_int_sort(ctx));
+    return mk_var(ctx, name, Z3_mk_int_sort(ctx));
 }
 
 
@@ -29,13 +29,15 @@ static void tst_get_implied_equalities1() {
     unsigned i;
     Z3_ast terms[7] = { a, b, c, d, fa, fb, fc };
     unsigned class_ids[7] = { 0, 0, 0, 0, 0, 0, 0 };
+    Z3_solver solver = Z3_mk_simple_solver(ctx);
+    Z3_solver_inc_ref(ctx, solver);
         
-    Z3_assert_cnstr(ctx, Z3_mk_eq(ctx, a, b));
-    Z3_assert_cnstr(ctx, Z3_mk_eq(ctx, b, d));
-    Z3_assert_cnstr(ctx, Z3_mk_le(ctx, fa, fc));
-    Z3_assert_cnstr(ctx, Z3_mk_le(ctx, fc, d));
+    Z3_solver_assert(ctx, solver, Z3_mk_eq(ctx, a, b));
+    Z3_solver_assert(ctx, solver, Z3_mk_eq(ctx, b, d));
+    Z3_solver_assert(ctx, solver, Z3_mk_le(ctx, fa, fc));
+    Z3_solver_assert(ctx, solver, Z3_mk_le(ctx, fc, d));
     
-    Z3_get_implied_equalities(ctx, num_terms, terms, class_ids);
+    Z3_get_implied_equalities(ctx, solver, num_terms, terms, class_ids);
     for (i = 0; i < num_terms; ++i) {
         printf("Class %s |-> %d\n", Z3_ast_to_string(ctx, terms[i]), class_ids[i]);
     }
@@ -48,8 +50,8 @@ static void tst_get_implied_equalities1() {
     SASSERT(class_ids[4] == class_ids[5]);
 
     printf("asserting b <= f(a)\n");
-    Z3_assert_cnstr(ctx, Z3_mk_le(ctx, b, fa));
-    Z3_get_implied_equalities(ctx, num_terms, terms, class_ids);
+    Z3_solver_assert(ctx, solver, Z3_mk_le(ctx, b, fa));
+    Z3_get_implied_equalities(ctx, solver, num_terms, terms, class_ids);
     for (i = 0; i < num_terms; ++i) {
         printf("Class %s |-> %d\n", Z3_ast_to_string(ctx, terms[i]), class_ids[i]);
     }
@@ -61,6 +63,7 @@ static void tst_get_implied_equalities1() {
     SASSERT(class_ids[6] == class_ids[0]);
 
     
+    Z3_solver_dec_ref(ctx, solver);
     /* delete logical context */
     Z3_del_context(ctx);    
 }
@@ -72,6 +75,8 @@ static void tst_get_implied_equalities2() {
     Z3_config cfg = Z3_mk_config();
     Z3_context ctx = Z3_mk_context(cfg);
     Z3_del_config(cfg);
+    Z3_solver solver = Z3_mk_simple_solver(ctx);
+    Z3_solver_inc_ref(ctx, solver);
     Z3_sort int_ty = Z3_mk_int_sort(ctx);
     Z3_ast a = mk_int_var(ctx,"a");
     Z3_ast b = mk_int_var(ctx,"b");
@@ -87,7 +92,7 @@ static void tst_get_implied_equalities2() {
     Z3_ast terms[5] = { x, y, z, u, v};
     unsigned class_ids[5] = { 0, 0, 0, 0, 0};
     
-    Z3_get_implied_equalities(ctx, num_terms, terms, class_ids);
+    Z3_get_implied_equalities(ctx, solver, num_terms, terms, class_ids);
     for (i = 0; i < num_terms; ++i) {
         printf("Class %s |-> %d\n", Z3_ast_to_string(ctx, terms[i]), class_ids[i]);
     }
@@ -100,9 +105,10 @@ static void tst_get_implied_equalities2() {
     SASSERT(class_ids[2] != class_ids[1]);
     SASSERT(class_ids[3] != class_ids[1]);
     SASSERT(class_ids[4] != class_ids[1]);  
-	SASSERT(class_ids[3] != class_ids[2]);
+    SASSERT(class_ids[3] != class_ids[2]);
 
     /* delete logical context */
+    Z3_solver_dec_ref(ctx, solver);
     Z3_del_context(ctx);    
 }
 
diff --git a/src/test/model_retrieval.cpp b/src/test/model_retrieval.cpp
index da6c3ddd0..f40f89d22 100644
--- a/src/test/model_retrieval.cpp
+++ b/src/test/model_retrieval.cpp
@@ -18,7 +18,7 @@ void tst_model_retrieval()
     ast_manager m;
     reg_decl_plugins(m);
 
-    family_id array_fid = m.get_family_id(symbol("array"));
+    family_id array_fid = m.mk_family_id(symbol("array"));
     array_util au(m);
     
     // arr_s and select_fn creation copy-pasted from z3.cpp
diff --git a/src/util/cancel_eh.h b/src/util/cancel_eh.h
index 74c5040a2..0401e6f03 100644
--- a/src/util/cancel_eh.h
+++ b/src/util/cancel_eh.h
@@ -29,6 +29,7 @@ class cancel_eh : public event_handler {
     T & m_obj;
 public:
     cancel_eh(T & o):m_obj(o) {}
+    ~cancel_eh() { m_obj.reset_cancel(); }
     virtual void operator()() { 
         m_obj.cancel(); 
     }
diff --git a/src/util/gparams.cpp b/src/util/gparams.cpp
index 1305a1e02..8b1fbe40e 100644
--- a/src/util/gparams.cpp
+++ b/src/util/gparams.cpp
@@ -52,6 +52,7 @@ char const * g_params_renames[] = {
     "qi_cost", "smt.qi.cost",
     "qi_eager_threshold", "smt.qi.eager_threshold",
     "nl_arith", "smt.arith.nl",
+    "pull_nested_quantifiers", "smt.pull_nested_quantifiers",
     "nnf_sk_hack", "nnf.sk_hack",
     "model_v2", "model.v2",
     "pi_non_nested_arith_weight", "pi.non_nested_arith_weight",
diff --git a/src/util/rational.cpp b/src/util/rational.cpp
index 0a91bd8da..122db7217 100644
--- a/src/util/rational.cpp
+++ b/src/util/rational.cpp
@@ -27,6 +27,31 @@ synch_mpq_manager *  rational::g_mpq_manager = 0;
 rational             rational::m_zero(0);
 rational             rational::m_one(1);
 rational             rational::m_minus_one(-1);
+vector<rational>     rational::m_powers_of_two;
+
+void mk_power_up_to(vector<rational> & pws, unsigned n) {
+    if (pws.empty()) {
+        pws.push_back(rational(1));
+    }
+    unsigned sz = pws.size();
+    rational curr = pws[sz - 1];
+    rational two(2);
+    for (unsigned i = sz; i <= n; i++) {
+        curr *= two;
+        pws.push_back(curr);
+    }
+}
+
+rational rational::power_of_two(unsigned k) {
+    rational result;
+    #pragma omp critical (powers_of_two)
+    {
+        if (k >= m_powers_of_two.size())
+            mk_power_up_to(m_powers_of_two, k+1);
+        result = m_powers_of_two[k];
+    }
+    return result;
+}
 
 void rational::initialize() {
     if (!g_mpq_manager) {
@@ -35,6 +60,7 @@ void rational::initialize() {
 }
 
 void rational::finalize() {
+    m_powers_of_two.finalize();
     dealloc(g_mpq_manager);
     g_mpq_manager = 0;
 }
diff --git a/src/util/rational.h b/src/util/rational.h
index f0406f30a..fc03228bf 100644
--- a/src/util/rational.h
+++ b/src/util/rational.h
@@ -26,14 +26,13 @@ class rational {
     static rational                  m_zero;
     static rational                  m_one;
     static rational                  m_minus_one;
-
+    static vector<rational>          m_powers_of_two;
     static synch_mpq_manager *       g_mpq_manager;
-
+    
     static synch_mpq_manager & m() { return *g_mpq_manager; }
 
 public:
     static void initialize();
-
     static void finalize();
     /*
       ADD_INITIALIZER('rational::initialize();')
@@ -272,6 +271,8 @@ public:
         return result;
     }
 
+    static rational power_of_two(unsigned k);
+
     bool is_power_of_two(unsigned & shift) {
         return m().is_power_of_two(m_val, shift);
     }
diff --git a/src/util/scoped_timer.cpp b/src/util/scoped_timer.cpp
index d475e5489..d0a79cec6 100644
--- a/src/util/scoped_timer.cpp
+++ b/src/util/scoped_timer.cpp
@@ -73,9 +73,6 @@ struct scoped_timer::imp {
     pthread_cond_t   m_condition_var;
 #elif defined(_LINUX_) || defined(_FREEBSD_)
     // Linux & FreeBSD
-    static void *   g_timer;
-    void            (*m_old_handler)(int);
-    void *          m_old_timer;
     timer_t         m_timerid;
 #else
     // Other
@@ -128,8 +125,9 @@ struct scoped_timer::imp {
         return st;
     }
 #elif defined(_LINUX_) || defined(_FREEBSD_)
-    static void sig_handler(int) {
-       static_cast<imp*>(g_timer)->m_eh->operator()();
+    static void sig_handler(union sigval s) {
+        void * ptr = s.sival_ptr;
+        static_cast<imp*>(ptr)->m_eh->operator()();
     }
 #else
     // Other
@@ -156,23 +154,11 @@ struct scoped_timer::imp {
             throw default_exception("failed to start timer thread");
 #elif defined(_LINUX_) || defined(_FREEBSD_)
 	// Linux & FreeBSD
-        if (omp_in_parallel()) {
-            // It doesn't work in with more than one thread.
-            // SIGEV_SIGNAL: the event is handled by the process not by the thread that installed the handler.
-            // SIGEV_THREAD: the event is handled by a new thread (Z3 crashes with this configuration).
-            // 
-            // It seems the way to go is SIGEV_SIGNAL, but I have to find a way to identify the thread the event is meant to.
-            return;
-        }
-	m_old_timer   = g_timer;
-	g_timer       = this;
-	m_old_handler = signal(SIG, sig_handler);
-
 	struct sigevent sev;
         memset(&sev, 0, sizeof(sigevent));
-	sev.sigev_notify = SIGEV_SIGNAL;
-	sev.sigev_signo  = SIG;
-	sev.sigev_value.sival_ptr = &m_timerid;
+	sev.sigev_notify = SIGEV_THREAD;
+        sev.sigev_value.sival_ptr = this;
+        sev.sigev_notify_function = sig_handler;
 	if (timer_create(CLOCKID, &sev, &m_timerid) == -1)
 	    throw default_exception("failed to create timer");
 
@@ -182,6 +168,7 @@ struct scoped_timer::imp {
 	its.it_value.tv_nsec = nano % 1000000000ull;
 	its.it_interval.tv_sec  = 0; // timer experies once
 	its.it_interval.tv_nsec = 0;
+        
 	if (timer_settime(m_timerid, 0, &its, NULL) == -1)
 	    throw default_exception("failed to set timer");
 #else
@@ -203,12 +190,7 @@ struct scoped_timer::imp {
             throw default_exception("failed to destroy pthread attributes object");
 #elif defined(_LINUX_) || defined(_FREEBSD_)
 	// Linux & FreeBSD
-        if (omp_in_parallel())
-            return; // see comments in the constructor.
 	timer_delete(m_timerid);
-	if (m_old_handler != SIG_ERR)
-	    signal(SIG, m_old_handler);
-	g_timer = m_old_timer;
 #else
 	// Other Platforms
 #endif
@@ -216,16 +198,6 @@ struct scoped_timer::imp {
 
 };
 
-#if defined(_WINDOWS) || defined(_CYGWIN)
-#elif defined(__APPLE__) && defined(__MACH__)
-// Mac OS X
-#elif defined(_LINUX_) || defined(_FREEBSD_)
-// Linux & FreeBSD
-void * scoped_timer::imp::g_timer = 0;
-#else
-// Other platforms
-#endif
-
 scoped_timer::scoped_timer(unsigned ms, event_handler * eh) {
     if (ms != UINT_MAX)
         m_imp = alloc(imp, ms, eh);