diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index e2703bdcb..7ac026673 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -24,6 +24,8 @@ Version 4.3.2
 
 - Added new option to mk_make to allow users to specify where python bindings (Z3Py) will be installed. (Thanks to Dejan Jovanovic for reporting the problem).
 
+- Fixed crash reported at http://z3.codeplex.com/workitem/10
+
 Version 4.3.1
 =============
 
diff --git a/src/api/api_algebraic.cpp b/src/api/api_algebraic.cpp
index 38f0289e6..3751c82ee 100644
--- a/src/api/api_algebraic.cpp
+++ b/src/api/api_algebraic.cpp
@@ -22,6 +22,10 @@ Notes:
 #include"api_log_macros.h"
 #include"api_context.h"
 #include"algebraic_numbers.h"
+#include"expr2polynomial.h"
+#include"cancel_eh.h"
+#include"scoped_timer.h"
+#include"api_ast_vector.h"
 
 extern "C" {
 
@@ -318,12 +322,67 @@ extern "C" {
         return !Z3_algebraic_eq(c, a, b);
     }
 
+    static bool to_anum_vector(Z3_context c, unsigned n, Z3_ast a[], scoped_anum_vector & as) {
+        algebraic_numbers::manager & _am = am(c);
+        scoped_anum tmp(_am);
+        for (unsigned i = 0; i < n; i++) {
+            if (is_rational(c, a[i])) {
+                _am.set(tmp, get_rational(c, a[i]).to_mpq());       
+                as.push_back(tmp);
+            }
+            else if (is_irrational(c, a[i])) {
+                as.push_back(get_irrational(c, a[i]));
+            }
+            else {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    class vector_var2anum : public polynomial::var2anum {
+        scoped_anum_vector const & m_as;
+    public:
+        vector_var2anum(scoped_anum_vector & as):m_as(as) {}
+        virtual ~vector_var2anum() {}
+        virtual algebraic_numbers::manager & m() const { return m_as.m(); }
+        virtual bool contains(polynomial::var x) const { return static_cast<unsigned>(x) < m_as.size(); }
+        virtual algebraic_numbers::anum const & operator()(polynomial::var x) const { return m_as.get(x); }
+    };
+
     Z3_ast_vector Z3_API Z3_algebraic_roots(Z3_context c, Z3_ast p, unsigned n, Z3_ast a[]) {
         Z3_TRY;
         LOG_Z3_algebraic_roots(c, p, n, a);
         RESET_ERROR_CODE();
-        // TODO
-        return 0;
+        polynomial::manager & pm = mk_c(c)->pm();
+        polynomial_ref _p(pm);
+        polynomial::scoped_numeral d(pm.m());
+        expr2polynomial converter(mk_c(c)->m(), pm, 0, true);
+        if (!converter.to_polynomial(to_expr(p), _p, d) ||
+            static_cast<unsigned>(max_var(_p)) >= n + 1) {
+            SET_ERROR_CODE(Z3_INVALID_ARG);
+            return 0;
+        }
+        algebraic_numbers::manager & _am = am(c);
+        scoped_anum_vector as(_am);
+        if (!to_anum_vector(c, n, a, as)) {
+            SET_ERROR_CODE(Z3_INVALID_ARG);
+            return 0;
+        }
+        scoped_anum_vector roots(_am);
+        {
+            cancel_eh<algebraic_numbers::manager> eh(_am);
+            api::context::set_interruptable(*(mk_c(c)), eh);
+            scoped_timer timer(mk_c(c)->params().m_timeout, &eh);
+            vector_var2anum v2a(as);
+            _am.isolate_roots(_p, v2a, roots);
+        }
+        Z3_ast_vector_ref* result = alloc(Z3_ast_vector_ref, mk_c(c)->m());
+        mk_c(c)->save_object(result);
+        for (unsigned i = 0; i < roots.size(); i++) {
+            result->m_ast_vector.push_back(au(c).mk_numeral(roots.get(i), false));
+        }
+        RETURN_Z3(of_ast_vector(result));
         Z3_CATCH_RETURN(0);
     }
 
@@ -331,8 +390,31 @@ extern "C" {
         Z3_TRY;
         LOG_Z3_algebraic_eval(c, p, n, a);
         RESET_ERROR_CODE();
-        // TODO
-        return 0;
+        polynomial::manager & pm = mk_c(c)->pm();
+        polynomial_ref _p(pm);
+        polynomial::scoped_numeral d(pm.m());
+        expr2polynomial converter(mk_c(c)->m(), pm, 0, true);
+        if (!converter.to_polynomial(to_expr(p), _p, d) ||
+            static_cast<unsigned>(max_var(_p)) >= n) {
+            SET_ERROR_CODE(Z3_INVALID_ARG);
+            return 0;
+        }
+        algebraic_numbers::manager & _am = am(c);
+        scoped_anum_vector as(_am);
+        if (!to_anum_vector(c, n, a, as)) {
+            SET_ERROR_CODE(Z3_INVALID_ARG);
+            return 0;
+        }
+        {
+            cancel_eh<algebraic_numbers::manager> eh(_am);
+            api::context::set_interruptable(*(mk_c(c)), eh);
+            scoped_timer timer(mk_c(c)->params().m_timeout, &eh);
+            vector_var2anum v2a(as);
+            int r = _am.eval_sign_at(_p, v2a);
+            if (r > 0) return 1;
+            else if (r < 0) return -1;
+            else return 0;
+        }
         Z3_CATCH_RETURN(0);
     }
 
diff --git a/src/api/api_context.cpp b/src/api/api_context.cpp
index 1d2b22059..7dc8d1a12 100644
--- a/src/api/api_context.cpp
+++ b/src/api/api_context.cpp
@@ -82,13 +82,13 @@ namespace api {
     context::context(context_params * p, bool user_ref_count):
         m_params(p != 0 ? *p : context_params()),
         m_user_ref_count(user_ref_count),
-        m_manager(m_params.m_proof ? PGM_FINE : PGM_DISABLED, m_params.m_trace ? m_params.m_trace_file_name.c_str() : 0), 
-        m_plugins(m_manager),
-        m_arith_util(m_manager),
-        m_bv_util(m_manager),
-        m_datalog_util(m_manager),
-        m_last_result(m_manager),
-        m_ast_trail(m_manager),
+        m_manager(m_params.mk_ast_manager()),
+        m_plugins(m()),
+        m_arith_util(m()),
+        m_bv_util(m()),
+        m_datalog_util(m()),
+        m_last_result(m()),
+        m_ast_trail(m()),
         m_replay_stack() {
 
         m_solver     = 0;
@@ -102,22 +102,16 @@ namespace api {
         m_smtlib_parser_has_decls = false;
         
         z3_bound_num_procs();
-        //
-        // Configuration parameter settings.
-        //
-        if (m_params.m_debug_ref_count) {
-            m_manager.debug_ref_count();
-        }
         
         m_error_handler = &default_error_handler;
 
-        m_basic_fid = m_manager.get_basic_family_id();
-        m_arith_fid = m_manager.get_family_id("arith");
-        m_bv_fid    = m_manager.get_family_id("bv");
-        m_array_fid = m_manager.get_family_id("array");
-        m_dt_fid    = m_manager.get_family_id("datatype");
-        m_datalog_fid = m_manager.get_family_id("datalog_relation");
-        m_dt_plugin = static_cast<datatype_decl_plugin*>(m_manager.get_plugin(m_dt_fid));
+        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_dt_plugin = static_cast<datatype_decl_plugin*>(m().get_plugin(m_dt_fid));
 
         if (!m_user_ref_count) {
             m_replay_stack.push_back(0);
@@ -143,7 +137,7 @@ namespace api {
         {
             if (m_interruptable)
                 (*m_interruptable)();
-            m_manager.set_cancel(true);
+            m().set_cancel(true);
         }
     }
     
@@ -196,12 +190,12 @@ namespace api {
     expr * context::mk_and(unsigned num_exprs, expr * const * exprs) {
         switch(num_exprs) {
         case 0: 
-            return m_manager.mk_true(); 
+            return m().mk_true(); 
         case 1: 
             save_ast_trail(exprs[0]);
             return exprs[0];
         default: {
-            expr * a = m_manager.mk_and(num_exprs, exprs);
+            expr * a = m().mk_and(num_exprs, exprs);
             save_ast_trail(a);
             return a;
         } }
@@ -217,7 +211,7 @@ namespace api {
         SASSERT(m_replay_stack.size() > num_scopes);
         unsigned j = m_replay_stack.size() - num_scopes - 1;
         if (!m_replay_stack[j]) {
-            m_replay_stack[j] = alloc(ast_ref_vector, m_manager);
+            m_replay_stack[j] = alloc(ast_ref_vector, m());
         }
         m_replay_stack[j]->push_back(n);
     }
@@ -325,7 +319,7 @@ namespace api {
     smt::kernel & context::get_smt_kernel() {
         if (!m_solver) {
             m_fparams.updt_params(m_params);
-            m_solver = alloc(smt::kernel, m_manager, m_fparams);
+            m_solver = alloc(smt::kernel, m(), m_fparams);
         }
         return *m_solver;
     }
diff --git a/src/api/api_context.h b/src/api/api_context.h
index a126f0790..edb79b2d5 100644
--- a/src/api/api_context.h
+++ b/src/api/api_context.h
@@ -32,6 +32,7 @@ Revision History:
 #include"event_handler.h"
 #include"tactic_manager.h"
 #include"context_params.h"
+#include"api_polynomial.h"
 
 namespace smtlib {
     class parser;
@@ -45,7 +46,7 @@ namespace api {
         struct add_plugins {  add_plugins(ast_manager & m); };
         context_params             m_params;
         bool                       m_user_ref_count; //!< if true, the user is responsible for managing referenc counters.
-        ast_manager                m_manager;
+        scoped_ptr<ast_manager>    m_manager;
         add_plugins                m_plugins;
 
         arith_util                 m_arith_util;
@@ -81,6 +82,8 @@ namespace api {
         Z3_ast_print_mode          m_print_mode;
 
         event_handler *            m_interruptable; // Reference to an object that can be interrupted by Z3_interrupt
+
+        pmanager                   m_pmanager;
     public:
         // Scoped obj for setting m_interruptable
         class set_interruptable {
@@ -98,10 +101,10 @@ namespace api {
         
         context(context_params * p, bool user_ref_count = false);
         ~context();
-        ast_manager & m() { return m_manager; }
+        ast_manager & m() const { return *(m_manager.get()); }
 
         context_params & params() { return m_params; }
-        bool produce_proofs() const { return m_manager.proofs_enabled(); }
+        bool produce_proofs() const { return m().proofs_enabled(); }
         bool produce_models() const { return m_params.m_model; }
         bool produce_unsat_cores() const { return m_params.m_unsat_core; }
         bool use_auto_config() const { return m_params.m_auto_config; }
@@ -167,6 +170,13 @@ namespace api {
 
         void check_sorts(ast * n);
 
+        // ------------------------
+        //
+        // Polynomial manager & caches
+        //
+        // -----------------------
+        polynomial::manager & pm() { return m_pmanager.pm(); }
+
         // ------------------------
         //
         // Solver interface for backward compatibility 
diff --git a/src/api/api_polynomial.cpp b/src/api/api_polynomial.cpp
new file mode 100644
index 000000000..af5803369
--- /dev/null
+++ b/src/api/api_polynomial.cpp
@@ -0,0 +1,34 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    api_polynomial.cpp
+
+Abstract:
+
+    Polynomial manager and caches for the external API.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2012-12-08
+
+Notes:
+    
+--*/
+#include"api_polynomial.h"
+
+namespace api {
+
+    pmanager::pmanager():
+        m_pm(m_nm) {
+    }
+
+    pmanager::~pmanager() {
+    }
+    
+    void pmanager::set_cancel(bool f) {
+        m_pm.set_cancel(f);
+    }
+
+};
diff --git a/src/api/api_polynomial.h b/src/api/api_polynomial.h
new file mode 100644
index 000000000..27317a7dd
--- /dev/null
+++ b/src/api/api_polynomial.h
@@ -0,0 +1,39 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    api_polynomial.h
+
+Abstract:
+
+    Polynomial manager and caches for the external API.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2012-12-08
+
+Notes:
+    
+--*/
+#ifndef _API_POLYNOMIAL_H_
+#define _API_POLYNOMIAL_H_
+
+#include"polynomial.h"
+
+namespace api {
+    
+    class pmanager {
+        unsynch_mpz_manager m_nm;
+        polynomial::manager m_pm;
+        // TODO: add support for caching expressions -> polynomial and back
+    public:
+        pmanager();
+        virtual ~pmanager();
+        polynomial::manager & pm() { return m_pm; }
+        void set_cancel(bool f);
+    };
+
+};
+
+#endif
diff --git a/src/api/python/z3.py b/src/api/python/z3.py
index 6517de221..924ac0ea5 100644
--- a/src/api/python/z3.py
+++ b/src/api/python/z3.py
@@ -1126,6 +1126,27 @@ def Var(idx, s):
         _z3_assert(is_sort(s), "Z3 sort expected")
     return _to_expr_ref(Z3_mk_bound(s.ctx_ref(), idx, s.ast), s.ctx)
 
+def RealVar(idx, ctx=None):
+    """
+    Create a real free variable. Free variables are used to create quantified formulas.
+    They are also used to create polynomials.
+    
+    >>> RealVar(0)
+    Var(0)
+    """
+    return Var(idx, RealSort(ctx))
+
+def RealVarVector(n, ctx=None):
+    """
+    Create a list of Real free variables.
+    The variables have ids: 0, 1, ..., n-1
+    
+    >>> x0, x1, x2, x3 = RealVarVector(4)
+    >>> x2
+    Var(2)
+    """
+    return [ RealVar(i, ctx) for i in range(n) ]
+
 #########################################
 #
 # Booleans
diff --git a/src/api/python/z3num.py b/src/api/python/z3num.py
index 27244a018..581536e44 100644
--- a/src/api/python/z3num.py
+++ b/src/api/python/z3num.py
@@ -58,6 +58,29 @@ class Numeral:
     True
     >>> Numeral(m[x])**2
     2
+    
+    We can also isolate the roots of polynomials.
+
+    >>> x0, x1, x2 = RealVarVector(3)
+    >>> r0 = isolate_roots(x0**5 - x0 - 1)
+    >>> r0
+    [1.1673039782?]
+    
+    In the following example, we are isolating the roots
+    of a univariate polynomial (on x1) obtained after substituting
+    x0 -> r0[0]
+    
+    >>> r1 = isolate_roots(x1**2 - x0 + 1, [ r0[0] ])
+    >>> r1
+    [-0.4090280898?, 0.4090280898?]
+    
+    Similarly, in the next example we isolate the roots of
+    a univariate polynomial (on x2) obtained after substituting
+    x0 -> r0[0] and x1 -> r1[0]
+
+    >>> isolate_roots(x1*x2 + x0, [ r0[0], r1[0] ])
+    [2.8538479564?]
+
     """
     def __init__(self, num, ctx=None):
         if isinstance(num, Ast):
@@ -481,6 +504,58 @@ class Numeral:
 
     def ctx_ref(self):
         return self.ctx.ref()
+
+def eval_sign_at(p, vs):
+    """ 
+    Evaluate the sign of the polynomial `p` at `vs`.  `p` is a Z3
+    Expression containing arithmetic operators: +, -, *, ^k where k is
+    an integer; and free variables x that is_var(x) is True. Moreover,
+    all variables must be real.
+    
+    The result is 1 if the polynomial is positive at the given point,
+    -1 if negative, and 0 if zero.
+
+    >>> x0, x1, x2 = RealVarVector(3)
+    >>> eval_sign_at(x0**2 + x1*x2 + 1, (Numeral(0), Numeral(1), Numeral(2)))
+    1
+    >>> eval_sign_at(x0**2 - 2, [ Numeral(Sqrt(2)) ])
+    0
+    >>> eval_sign_at((x0 + x1)*(x0 + x2), (Numeral(0), Numeral(Sqrt(2)), Numeral(Sqrt(3))))
+    1
+    """
+    num = len(vs)
+    _vs = (Ast * num)()
+    for i in range(num):
+        _vs[i] = vs[i].ast
+    return Z3_algebraic_eval(p.ctx_ref(), p.as_ast(), num, _vs)
+
+def isolate_roots(p, vs=[]):
+    """
+    Given a multivariate polynomial p(x_0, ..., x_{n-1}, x_n), returns the 
+    roots of the univariate polynomial p(vs[0], ..., vs[len(vs)-1], x_n).
+       
+    Remarks:
+    * p is a Z3 expression that contains only arithmetic terms and free variables.
+    * forall i in [0, n) vs is a numeral.
+    
+    The result is a list of numerals
+
+    >>> x0 = RealVar(0)
+    >>> isolate_roots(x0**5 - x0 - 1)
+    [1.1673039782?]
+    >>> x1 = RealVar(1)
+    >>> isolate_roots(x0**2 - x1**4 - 1, [ Numeral(Sqrt(3)) ])
+    [-1.1892071150?, 1.1892071150?]
+    >>> x2 = RealVar(2)
+    >>> isolate_roots(x2**2 + x0 - x1, [ Numeral(Sqrt(3)), Numeral(Sqrt(2)) ])
+    []
+    """
+    num = len(vs)
+    _vs = (Ast * num)()
+    for i in range(num):
+        _vs[i] = vs[i].ast
+    _roots = AstVector(Z3_algebraic_roots(p.ctx_ref(), p.as_ast(), num, _vs), p.ctx)
+    return [ Numeral(r) for r in _roots ]
         
 if __name__ == "__main__":
     import doctest
diff --git a/src/ast/expr2polynomial.cpp b/src/ast/expr2polynomial.cpp
index 72bd72aa7..fbabcb150 100644
--- a/src/ast/expr2polynomial.cpp
+++ b/src/ast/expr2polynomial.cpp
@@ -49,21 +49,24 @@ struct expr2polynomial::imp {
     polynomial::polynomial_ref_vector  m_presult_stack;
     polynomial::scoped_numeral_vector  m_dresult_stack;
 
+    bool                               m_use_var_idxs;
+
     volatile bool                      m_cancel;
     
-    imp(expr2polynomial & w, ast_manager & am, polynomial::manager & pm, expr2var * e2v):
+    imp(expr2polynomial & w, ast_manager & am, polynomial::manager & pm, expr2var * e2v, bool use_var_idxs):
         m_wrapper(w),
         m_am(am),
         m_autil(am),
         m_pm(pm),
-        m_expr2var(e2v == 0 ? alloc(expr2var, am) : e2v),
-        m_expr2var_owner(e2v == 0),
+        m_expr2var(e2v == 0 && !use_var_idxs ? alloc(expr2var, am) : e2v),
+        m_expr2var_owner(e2v == 0 && !use_var_idxs),
         m_var2expr(am),
         m_cached_domain(am),
         m_cached_polynomials(pm),
         m_cached_denominators(pm.m()),
         m_presult_stack(pm),
         m_dresult_stack(pm.m()),
+        m_use_var_idxs(use_var_idxs),
         m_cancel(false) {
     }
 
@@ -95,6 +98,14 @@ struct expr2polynomial::imp {
         cooperate("expr2polynomial");
     }
 
+    void throw_not_polynomial() {
+        throw default_exception("the given expression is not a polynomial");
+    }
+
+    void throw_no_int_var() {
+        throw default_exception("integer variables are not allowed in the given polynomial");
+    }
+
     void push_frame(app * t) {
         m_frame_stack.push_back(frame(t));
     }
@@ -127,14 +138,26 @@ struct expr2polynomial::imp {
     }
 
     void store_var_poly(expr * t) {
-        polynomial::var x = m_expr2var->to_var(t);
-        if (x == UINT_MAX) {
-            bool is_int = m_autil.is_int(t);
-            x = m_wrapper.mk_var(is_int);
-            m_expr2var->insert(t, x);
-            if (x >= m_var2expr.size())
-                m_var2expr.resize(x+1, 0);
-            m_var2expr.set(x, t);
+        polynomial::var x;
+        if (m_use_var_idxs) {
+            SASSERT(::is_var(t));
+            if (m_autil.is_int(t))
+                throw_no_int_var();
+            unsigned idx = to_var(t)->get_idx();
+            while (idx >= m_pm.num_vars())
+                m_pm.mk_var();
+            x = static_cast<polynomial::var>(idx);
+        }
+        else {
+            x = m_expr2var->to_var(t);
+            if (x == UINT_MAX) {
+                bool is_int = m_autil.is_int(t);
+                x = m_wrapper.mk_var(is_int);
+                m_expr2var->insert(t, x);
+                if (x >= m_var2expr.size())
+                    m_var2expr.resize(x+1, 0);
+                m_var2expr.set(x, t);
+            }
         }
         polynomial::numeral one(1);
         store_result(t, pm().mk_polynomial(x), one);
@@ -160,7 +183,10 @@ struct expr2polynomial::imp {
             rational k;
             SASSERT(t->get_num_args() == 2);
             if (!m_autil.is_numeral(t->get_arg(1), k) || !k.is_int() || !k.is_unsigned()) {
-                store_var_poly(t);
+                if (m_use_var_idxs)
+                    throw_not_polynomial();
+                else
+                    store_var_poly(t);
                 return true;
             }
             push_frame(t);
@@ -168,6 +194,8 @@ struct expr2polynomial::imp {
         }
         default:
             // can't handle operator
+            if (m_use_var_idxs)
+                throw_not_polynomial();
             store_var_poly(t);
             return true;
         }
@@ -190,6 +218,8 @@ struct expr2polynomial::imp {
         
         SASSERT(is_app(t));
         if (!m_autil.is_arith_expr(t)) {
+            if (m_use_var_idxs)
+                throw_not_polynomial();
             store_var_poly(t);
             return true;
         }
@@ -378,19 +408,25 @@ struct expr2polynomial::imp {
 
         for (unsigned i = 0; i < sz; i++) {
             margs.reset();
-            polynomial::monomial * m = pm().get_monomial(p, i);
+            polynomial::monomial * _m = pm().get_monomial(p, i);
             polynomial::numeral const & a = pm().coeff(p, i);
             if (!nm().is_one(a)) {
                 margs.push_back(m_autil.mk_numeral(rational(a), is_int));
             }
-            unsigned msz = pm().size(m);
+            unsigned msz = pm().size(_m);
             for (unsigned j = 0; j < msz; j++) {
-                polynomial::var x = pm().get_var(m, j);
-                expr * t = m_var2expr.get(x);
-                if (m_wrapper.is_int(x) && !is_int) {
-                    t = m_autil.mk_to_real(t);
+                polynomial::var x = pm().get_var(_m, j);
+                expr * t;
+                if (m_use_var_idxs) {
+                    t = m().mk_var(x, m_autil.mk_real());
                 }
-                unsigned d = pm().degree(m, j);
+                else {
+                    t = m_var2expr.get(x);
+                    if (m_wrapper.is_int(x) && !is_int) {
+                        t = m_autil.mk_to_real(t);
+                    }
+                }
+                unsigned d = pm().degree(_m, j);
                 if (use_power && d > 1) {
                     margs.push_back(m_autil.mk_power(t, m_autil.mk_numeral(rational(d), is_int)));
                 }
@@ -426,8 +462,8 @@ struct expr2polynomial::imp {
     }
 };
 
-expr2polynomial::expr2polynomial(ast_manager & am, polynomial::manager & pm, expr2var * e2v) {
-    m_imp = alloc(imp, *this, am, pm, e2v);
+expr2polynomial::expr2polynomial(ast_manager & am, polynomial::manager & pm, expr2var * e2v, bool use_var_idxs) {
+    m_imp = alloc(imp, *this, am, pm, e2v, use_var_idxs);
 }
 
 expr2polynomial::~expr2polynomial() {
@@ -451,10 +487,12 @@ void expr2polynomial::to_expr(polynomial::polynomial_ref const & p, bool use_pow
 }
 
 bool expr2polynomial::is_var(expr * t) const { 
+    SASSERT(!m_imp->m_use_var_idxs);
     return m_imp->m_expr2var->is_var(t); 
 }
     
 expr2var const & expr2polynomial::get_mapping() const { 
+    SASSERT(!m_imp->m_use_var_idxs);
     return *(m_imp->m_expr2var); 
 }
 
diff --git a/src/ast/expr2polynomial.h b/src/ast/expr2polynomial.h
index fbeda019d..8934f3f24 100644
--- a/src/ast/expr2polynomial.h
+++ b/src/ast/expr2polynomial.h
@@ -29,7 +29,24 @@ class expr2polynomial {
     struct imp;
     imp * m_imp;
 public:
-    expr2polynomial(ast_manager & am, polynomial::manager & pm, expr2var * e2v);
+    expr2polynomial(ast_manager & am, 
+                    polynomial::manager & pm, 
+                    expr2var * e2v,
+                    /*
+                      If true, the expressions converted into 
+                      polynomials should only contain Z3 free variables.
+                      A Z3 variable x, with idx i, is converted into
+                      the variable i of the polynomial manager pm.
+                      
+                      An exception is thrown if there is a mismatch between
+                      the sorts x and the variable in the polynomial manager.
+
+                      The argument e2v is ignored when use_var_idxs is true.
+
+                      Moreover, only real variables are allowed.
+                    */
+                    bool use_var_idxs = false
+                    );
     virtual ~expr2polynomial();
 
     ast_manager & m() const;
@@ -63,6 +80,8 @@ public:
     
     /**
        \brief Return the mapping from expressions to variables
+    
+       \pre the object was created using use_var_idxs = false.
     */
     expr2var const & get_mapping() const;
 
@@ -74,10 +93,10 @@ public:
     /**
        \brief Return true if the variable is associated with an expression of integer sort.
     */
-    virtual bool is_int(polynomial::var x) const = 0;
+    virtual bool is_int(polynomial::var x) const { UNREACHABLE(); return false; }
 
 protected:
-    virtual polynomial::var mk_var(bool is_int) = 0;
+    virtual polynomial::var mk_var(bool is_int) { UNREACHABLE(); return polynomial::null_var; }
 };
 
 class default_expr2polynomial : public expr2polynomial {
diff --git a/src/cmd_context/cmd_context.cpp b/src/cmd_context/cmd_context.cpp
index ae375fc99..828cc3a68 100644
--- a/src/cmd_context/cmd_context.cpp
+++ b/src/cmd_context/cmd_context.cpp
@@ -592,14 +592,9 @@ void cmd_context::init_manager() {
     SASSERT(m_manager == 0);
     SASSERT(m_pmanager == 0);
     m_check_sat_result = 0;
-    m_manager  = alloc(ast_manager, 
-                       produce_proofs() ? PGM_FINE : PGM_DISABLED, 
-                       m_params.m_trace ? m_params.m_trace_file_name.c_str() : 0);
+    m_manager  = m_params.mk_ast_manager();
     m_pmanager = alloc(pdecl_manager, *m_manager);
     init_manager_core(true);
-    // PARAM-TODO
-    // if (params().m_smtlib2_compliant)
-    //    m_manager->enable_int_real_coercions(false);
 }
 
 void cmd_context::init_external_manager() {
diff --git a/src/cmd_context/context_params.cpp b/src/cmd_context/context_params.cpp
index 96af5b52a..41ad5a423 100644
--- a/src/cmd_context/context_params.cpp
+++ b/src/cmd_context/context_params.cpp
@@ -79,6 +79,9 @@ void context_params::set(char const * param, char const * value) {
     else if (p == "debug_ref_count") {
         set_bool(m_debug_ref_count, param, value);
     }
+    else if (p == "smtlib2_compliant") {
+        set_bool(m_smtlib2_compliant, param, value);
+    }
     else {
         throw default_exception("unknown parameter '%s'", p.c_str());
     }
@@ -99,6 +102,7 @@ void context_params::updt_params(params_ref const & p) {
     m_trace_file_name   = p.get_str("trace_file_name", "z3.log");
     m_unsat_core        = p.get_bool("unsat_core", false);
     m_debug_ref_count   = p.get_bool("debug_ref_count", false);
+    m_smtlib2_compliant = p.get_bool("smtlib2_compliant", false);
 }
 
 void context_params::collect_param_descrs(param_descrs & d) {
@@ -113,6 +117,7 @@ void context_params::collect_param_descrs(param_descrs & d) {
     d.insert("trace_file_name", CPK_STRING, "trace out file name (see option 'trace')", "z3.log");
     d.insert("unsat_core", CPK_BOOL, "unsat-core generation for solvers, this parameter can be overwritten when creating a solver, not every solver in Z3 supports unsat core generation", "false");
     d.insert("debug_ref_count", CPK_BOOL, "debug support for AST reference counting", "false");
+    d.insert("smtlib2_compliant", CPK_BOOL, "enable/disable SMT-LIB 2.0 compliance", "false");
 }
 
 params_ref context_params::merge_default_params(params_ref const & p) {
@@ -133,4 +138,15 @@ void context_params::init_solver_params(ast_manager & m, solver & s, params_ref
     s.updt_params(merge_default_params(p));
 }
 
+ast_manager * context_params::mk_ast_manager() {
+    ast_manager * r = alloc(ast_manager, 
+                            m_proof ? PGM_FINE : PGM_DISABLED, 
+                            m_trace ? m_trace_file_name.c_str() : 0);
+    if (m_smtlib2_compliant)
+        r->enable_int_real_coercions(false);
+    if (m_debug_ref_count)
+        r->debug_ref_count();
+    return r;
+}
+
 
diff --git a/src/cmd_context/context_params.h b/src/cmd_context/context_params.h
index b3933dc23..dd60b9616 100644
--- a/src/cmd_context/context_params.h
+++ b/src/cmd_context/context_params.h
@@ -37,6 +37,7 @@ public:
     bool        m_model;
     bool        m_model_validate;
     bool        m_unsat_core;
+    bool        m_smtlib2_compliant; // it must be here because it enable/disable the use of coercions in the ast_manager.
     unsigned    m_timeout;
 
     context_params();
@@ -63,6 +64,11 @@ public:
        Example: auto_config
     */
     params_ref merge_default_params(params_ref const & p);
+    
+    /**
+       \brief Create an AST manager using this configuration.
+    */
+    ast_manager * mk_ast_manager();
 };
 
 
diff --git a/src/math/polynomial/algebraic_numbers.h b/src/math/polynomial/algebraic_numbers.h
index 4735a875b..a4669eae6 100644
--- a/src/math/polynomial/algebraic_numbers.h
+++ b/src/math/polynomial/algebraic_numbers.h
@@ -64,6 +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 updt_params(params_ref const & p);
 
diff --git a/src/parsers/smt2/smt2parser.cpp b/src/parsers/smt2/smt2parser.cpp
index ee93dca2f..c99c362bd 100644
--- a/src/parsers/smt2/smt2parser.cpp
+++ b/src/parsers/smt2/smt2parser.cpp
@@ -2365,7 +2365,7 @@ namespace smt2 {
         parser(cmd_context & ctx, std::istream & is, bool interactive, params_ref const & p):
             m_ctx(ctx), 
             m_params(p),
-            m_scanner(ctx, is, interactive, p), 
+            m_scanner(ctx, is, interactive),
             m_curr(scanner::NULL_TOKEN),
             m_curr_cmd(0),
             m_num_bindings(0),
diff --git a/src/parsers/smt2/smt2scanner.cpp b/src/parsers/smt2/smt2scanner.cpp
index e2b2030ac..0f6101a93 100644
--- a/src/parsers/smt2/smt2scanner.cpp
+++ b/src/parsers/smt2/smt2scanner.cpp
@@ -242,7 +242,7 @@ namespace smt2 {
         }
     }
     
-    scanner::scanner(cmd_context & ctx, std::istream& stream, bool interactive, params_ref const & _p):
+    scanner::scanner(cmd_context & ctx, std::istream& stream, bool interactive):
         m_ctx(ctx),
         m_interactive(interactive), 
         m_spos(0),
@@ -254,9 +254,8 @@ namespace smt2 {
         m_bend(0),
         m_stream(stream),
         m_cache_input(false) {
-
-        parser_params p(_p);
-        m_smtlib2_compliant = p.smt2_compliant();
+        
+        m_smtlib2_compliant = ctx.params().m_smtlib2_compliant;
 
         for (int i = 0; i < 256; ++i) {
             m_normalized[i] = (char) i;
diff --git a/src/parsers/smt2/smt2scanner.h b/src/parsers/smt2/smt2scanner.h
index c63a09ff1..7b74c752f 100644
--- a/src/parsers/smt2/smt2scanner.h
+++ b/src/parsers/smt2/smt2scanner.h
@@ -76,7 +76,7 @@ namespace smt2 {
             EOF_TOKEN
         };
         
-        scanner(cmd_context & ctx, std::istream& stream, bool interactive = false, params_ref const & p = params_ref());
+        scanner(cmd_context & ctx, std::istream& stream, bool interactive = false);
         
         ~scanner() {}    
         
diff --git a/src/parsers/util/parser_params.pyg b/src/parsers/util/parser_params.pyg
index fa8f17a00..3f7495f43 100644
--- a/src/parsers/util/parser_params.pyg
+++ b/src/parsers/util/parser_params.pyg
@@ -3,4 +3,4 @@ def_module_params('parser',
                   params=(('ignore_user_patterns', BOOL, False, 'ignore patterns provided by the user'),
                           ('ignore_bad_patterns',  BOOL, True, 'ignore malformed patterns'),
                           ('error_for_visual_studio', BOOL, False, 'display error messages in Visual Studio format'),
-                          ('smt2_compliant', BOOL, False, 'enable/disable SMT-LIB 2.0 compliance')))
+                          ))
diff --git a/src/smt/mam.cpp b/src/smt/mam.cpp
index 24b8e2e7c..c9d6ead88 100644
--- a/src/smt/mam.cpp
+++ b/src/smt/mam.cpp
@@ -142,6 +142,14 @@ namespace smt {
         }
     };
 
+    struct initn : public instruction {
+        // We need that because starting at Z3 3.0, some associative
+        // operators (e.g., + and *) are represented using n-ary
+        // applications.
+        // We do not need the extra field for INIT1, ..., INIT6.
+        unsigned       m_num_args; 
+    };
+
     struct compare : public instruction {
         unsigned       m_reg1;
         unsigned       m_reg2;
@@ -608,7 +616,18 @@ namespace smt {
         instruction * mk_init(unsigned n) { 
             SASSERT(n >= 1);
             opcode op = n <= 6 ? static_cast<opcode>(INIT1 + n - 1) : INITN;
-            return mk_instr<instruction>(op, sizeof(instruction)); 
+            if (op == INITN) {
+                // We store the actual number of arguments for INITN.
+                // Starting at Z3 3.0, some associative operators
+                // (e.g., + and *) are represented using n-ary
+                // applications.
+                initn * r = mk_instr<initn>(op, sizeof(initn));
+                r->m_num_args = n;
+                return r;
+            }
+            else {
+                return mk_instr<instruction>(op, sizeof(instruction));
+            }
         }
 
     public:
@@ -2345,6 +2364,8 @@ namespace smt {
         case INITN:
             m_app      = m_registers[0];
             m_num_args = m_app->get_num_args();
+            if (m_num_args != static_cast<const initn *>(m_pc)->m_num_args)
+                goto backtrack;
             for (unsigned i = 0; i < m_num_args; i++)
                 m_registers[i+1] = m_app->get_arg(i);
             m_pc = m_pc->m_next;
@@ -3982,3 +4003,8 @@ namespace smt {
     }
 };
 
+#ifdef Z3DEBUG
+void pp(smt::code_tree * c) {
+    c->display(std::cout);
+}
+#endif