diff --git a/src/api/z3_api.h b/src/api/z3_api.h
index 57e4d3ec1..397be7684 100644
--- a/src/api/z3_api.h
+++ b/src/api/z3_api.h
@@ -6023,7 +6023,7 @@ END_MLAPI_EXCLUDE
        \param a - arithmetical term       
        def_API('Z3_optimize_maximize', UINT, (_in(CONTEXT), _in(OPTIMIZE), _in(AST)))
     */
-    unsigned Z3_API Z3_optimize_maximize(Z3_context, Z3_optimize o, Z3_ast t);
+    unsigned Z3_API Z3_optimize_maximize(Z3_context c, Z3_optimize o, Z3_ast t);
 
     /**
        \brief Add a minimization constraint.
@@ -6033,7 +6033,7 @@ END_MLAPI_EXCLUDE
     
        def_API('Z3_optimize_minimize', UINT, (_in(CONTEXT), _in(OPTIMIZE), _in(AST)))
     */
-    unsigned Z3_API Z3_optimize_minimize(Z3_context, Z3_optimize o, Z3_ast t);
+    unsigned Z3_API Z3_optimize_minimize(Z3_context c, Z3_optimize o, Z3_ast t);
 
 
     /**
diff --git a/src/math/polynomial/polynomial.cpp b/src/math/polynomial/polynomial.cpp
index f5d96e740..3f1883749 100644
--- a/src/math/polynomial/polynomial.cpp
+++ b/src/math/polynomial/polynomial.cpp
@@ -4117,7 +4117,6 @@ namespace polynomial {
             polynomial_ref H(m_wrapper), C(m_wrapper);
             polynomial_ref lc_H(m_wrapper);
             unsigned min_deg_q = UINT_MAX;
-            var next_x         = vars[idx+1];
             unsigned counter   = 0;
 
             for (;; counter++) {
@@ -4137,7 +4136,7 @@ namespace polynomial {
                 var q_var      = max_var(q);
                 unsigned deg_q = q_var == null_var ? 0 : degree(q, q_var);
                 TRACE("mgcd_detail", tout << "counter: " << counter << "\nidx: " << idx << "\nq: " << q << "\ndeg_q: " << deg_q << "\nmin_deg_q: " << 
-                      min_deg_q << "\nnext_x: x" << next_x << "\nmax_var(q): " << q_var << "\n";);
+                      min_deg_q << "\nnext_x: x" << vars[idx+1] << "\nmax_var(q): " << q_var << "\n";);
                 if (deg_q < min_deg_q) {
                     TRACE("mgcd_detail", tout << "reseting...\n";);                    
                     counter   = 0;
@@ -5113,10 +5112,9 @@ namespace polynomial {
                 monomial const * m_r = R.m(max_R);
                 numeral const & a_r  = R.a(max_R);
                 monomial * m_r_q = 0;
-                bool q_div_r = div(m_r, m_q, m_r_q);
+                VERIFY(div(m_r, m_q, m_r_q));
                 TRACE("polynomial", tout << "m_r: "; m_r->display(tout); tout << "\nm_q: "; m_q->display(tout); tout << "\n";
                       if (m_r_q) { tout << "m_r_q: "; m_r_q->display(tout); tout << "\n"; });
-                SASSERT(q_div_r);
                 m_r_q_ref = m_r_q;
                 m_manager.div(a_r, a_q, a_r_q);
                 C.add(a_r_q, m_r_q);       // C <- C + (a_r/a_q)*(m_r/m_q)
diff --git a/src/muz/rel/udoc_relation.cpp b/src/muz/rel/udoc_relation.cpp
index d3c1f929d..4d1fdf1d2 100644
--- a/src/muz/rel/udoc_relation.cpp
+++ b/src/muz/rel/udoc_relation.cpp
@@ -1264,6 +1264,21 @@ namespace datalog {
         return check_kind(t)?alloc(filter_proj_fn, get(t), get_ast_manager(), condition, removed_col_cnt, removed_cols):0;
     }
 
+    relation_join_fn * udoc_plugin::mk_join_project_fn(
+        relation_base const& t1, relation_base const& t2,
+        unsigned joined_col_cnt, const unsigned * cols1, const unsigned * cols2, 
+        unsigned removed_col_cnt, const unsigned * removed_cols) {    
+        if (check_kind(t1) && check_kind(t2)) 
+            return 0;
+#if 0
+            return alloc(join_proj_fn, get(t1), ge(t2), 
+                         joined_col_cnt, cols1, cols2, 
+                         removed_col_cnt, removed_cols);   
+#endif     
+        else
+            return 0;
+    }
+
 
 
 
diff --git a/src/muz/rel/udoc_relation.h b/src/muz/rel/udoc_relation.h
index f040e4745..596a1f0dd 100644
--- a/src/muz/rel/udoc_relation.h
+++ b/src/muz/rel/udoc_relation.h
@@ -81,6 +81,7 @@ namespace datalog {
     class udoc_plugin : public relation_plugin {
         friend class udoc_relation;
         class join_fn;
+        class join_project_fn;
         class project_fn;
         class union_fn;
         class rename_fn;
@@ -138,6 +139,11 @@ namespace datalog {
         virtual relation_transformer_fn * mk_filter_interpreted_and_project_fn(
             const relation_base & t, app * condition,
             unsigned removed_col_cnt, const unsigned * removed_cols);
+        virtual relation_join_fn * mk_join_project_fn(
+            relation_base const& t1, relation_base const& t2,
+            unsigned joined_col_cnt, const unsigned * cols1, const unsigned * cols2, 
+            unsigned removed_col_cnt, const unsigned * removed_cols);
+             
         void disable_fast_pass() { m_disable_fast_pass = true; }
     };
 };
diff --git a/src/opt/inc_sat_solver.cpp b/src/opt/inc_sat_solver.cpp
index 5eecf42d7..1c450bbef 100644
--- a/src/opt/inc_sat_solver.cpp
+++ b/src/opt/inc_sat_solver.cpp
@@ -316,6 +316,7 @@ private:
         for (; it != end; ++it) {
             asms.push_back(it->m_value);
         }
+        //IF_VERBOSE(0, verbose_stream() << asms << "\n";);
     }
 
     void extract_core(dep2asm_t& dep2asm) {
@@ -341,7 +342,7 @@ private:
         m_core.reset();
         for (unsigned i = 0; i < core.size(); ++i) {
             expr* e;
-            VERIFY (asm2dep.find(core[i].index(), e));
+            VERIFY(asm2dep.find(core[i].index(), e));
             m_core.push_back(e);
         }
 
@@ -397,6 +398,14 @@ private:
         SASSERT(m_model);
         // IF_VERBOSE(0, model_smt2_pp(verbose_stream(), m, *(m_model.get()), 0););
 
+        DEBUG_CODE(
+            for (unsigned i = 0; i < m_fmls.size(); ++i) {
+                expr_ref tmp(m);
+                VERIFY(m_model->eval(m_fmls[i].get(), tmp));                
+                CTRACE("opt", !m.is_true(tmp),
+                       tout << "Evaluation failed: " << mk_pp(m_fmls[i].get(), m) << "\n";);
+                SASSERT(m.is_true(tmp));
+            });
     }
 };
 
diff --git a/src/opt/maxres.cpp b/src/opt/maxres.cpp
index be39a05d5..65e026c07 100644
--- a/src/opt/maxres.cpp
+++ b/src/opt/maxres.cpp
@@ -64,6 +64,7 @@ Notes:
 #include "pb_decl_plugin.h"
 #include "opt_params.hpp"
 #include "ast_util.h"
+#include "smt_solver.h"
 
 using namespace opt;
 
@@ -150,6 +151,7 @@ public:
     }
 
     void new_assumption(expr* e, rational const& w) {
+        IF_VERBOSE(3, verbose_stream() << "new assumption " << mk_pp(e, m) << " " << w << "\n";);
         TRACE("opt", tout << "insert: " << mk_pp(e, m) << " : " << w << "\n";);
         m_asm2weight.insert(e, w);
         m_asms.push_back(e);
@@ -171,7 +173,6 @@ public:
             if (m_cancel) {
                 return l_undef;
             }
-            model_ref mdl;
             switch (is_sat) {
             case l_true: 
                 found_optimum();
@@ -179,7 +180,6 @@ public:
             case l_false:
                 is_sat = process_unsat();
                 if (is_sat != l_true) return is_sat;
-                get_mus_model(mdl);
                 break;
             case l_undef:
                 return l_undef;
@@ -187,6 +187,7 @@ public:
                 break;
             }
         }
+        trace_bounds("maxres");
         return l_true;
     }
 
@@ -370,6 +371,7 @@ public:
     }
 
     void found_optimum() {
+        IF_VERBOSE(1, verbose_stream() << "found optimum\n";);
         s().get_model(m_model);
         DEBUG_CODE(
             for (unsigned i = 0; i < m_asms.size(); ++i) {
@@ -404,6 +406,9 @@ public:
         while (is_sat == l_false) {
             core.reset();
             s().get_unsat_core(core);
+            //verify_core(core);
+            model_ref mdl;
+            get_mus_model(mdl);
             is_sat = minimize_core(core);
             if (is_sat != l_true) {
                 break;
@@ -420,18 +425,12 @@ public:
                 break;
             }
             remove_soft(core, asms);
-            TRACE("opt",
-                  display_vec(tout << "core: ", core.size(), core.c_ptr());
-                  display_vec(tout << "assumptions: ", asms.size(), asms.c_ptr()););
             is_sat = check_sat_hill_climb(asms);
         }
         TRACE("opt", 
               tout << "num cores: " << cores.size() << "\n";
               for (unsigned i = 0; i < cores.size(); ++i) {
-                  for (unsigned j = 0; j < cores[i].size(); ++j) {
-                      tout << mk_pp(cores[i][j], m) << " ";
-                  }
-                  tout << "\n";
+                  display_vec(tout, cores[i].size(), cores[i].c_ptr());
               }
               tout << "num satisfying: " << asms.size() << "\n";);
         
@@ -535,6 +534,7 @@ public:
         if (m_c.sat_enabled()) {
             // SAT solver core extracts some model 
             // during unsat core computation.
+            mdl = 0;
             s().get_model(mdl);
         }
         else {
@@ -601,10 +601,7 @@ public:
         // find the minimal weight:
         rational w = get_weight(core[0]);
         for (unsigned i = 1; i < core.size(); ++i) {
-            rational w2 = get_weight(core[i]);
-            if (w2 < w) {
-                w = w2;
-            }
+            w = std::min(w, get_weight(core[i]));
         }
         // add fresh soft clauses for weights that are above w.
         for (unsigned i = 0; i < core.size(); ++i) {
@@ -614,6 +611,7 @@ public:
                 new_assumption(core[i], w3);
             }
         }
+        
         return w;
     }
 
@@ -754,6 +752,7 @@ public:
             case l_false:
                 core.reset();
                 s().get_unsat_core(core);
+                DEBUG_CODE(verify_core(core););
                 is_sat = minimize_core(core);
                 if (is_sat != l_true) {
                     break;
@@ -786,14 +785,9 @@ public:
         rational upper(0);
         expr_ref tmp(m);
         for (unsigned i = 0; i < m_soft.size(); ++i) {
-            expr* n = m_soft[i];
-            VERIFY(mdl->eval(n, tmp));
-            if (!m.is_true(tmp)) {
+            if (!is_true(mdl, m_soft[i])) {
                 upper += m_weights[i];
             }
-            TRACE("opt", tout << mk_pp(n, m) << " |-> " << mk_pp(tmp, m) << "\n";);
-            CTRACE("opt", !m.is_true(tmp) && !m.is_false(tmp), 
-                   tout << mk_pp(n, m) << " |-> " << mk_pp(tmp, m) << "\n";);
         }
         if (upper >= m_upper) {
             return;
@@ -804,7 +798,7 @@ public:
             m_assignment[i] = is_true(m_soft[i]);
         }
         m_upper = upper;
-        // verify_assignment();
+        DEBUG_CODE(verify_assignment(););
         trace_bounds("maxres");
 
         add_upper_bound_block();
@@ -888,6 +882,38 @@ public:
         }
     }
 
+    void verify_core(exprs const& core) {
+        IF_VERBOSE(3, verbose_stream() << "verify core\n";);        
+        ref<solver> sat_solver = mk_inc_sat_solver(m, m_params);
+
+        for (unsigned i = 0; i < s().get_num_assertions(); ++i) {
+            sat_solver->assert_expr(s().get_assertion(i));
+        }
+        expr_ref n(m);        
+        for (unsigned i = 0; i < core.size(); ++i) {
+            IF_VERBOSE(1, verbose_stream() << mk_pp(core[i],m) << " ";);
+            sat_solver->assert_expr(core[i]);
+        }
+        IF_VERBOSE(1, verbose_stream() << "\n";);
+        lbool is_sat = sat_solver->check_sat(0, 0);
+        if (is_sat != l_false) {
+            IF_VERBOSE(0, verbose_stream() << "!!!not a core\n";);
+        }        
+
+        sat_solver = mk_smt_solver(m, m_params, symbol());
+        for (unsigned i = 0; i < s().get_num_assertions(); ++i) {
+            sat_solver->assert_expr(s().get_assertion(i));
+        }
+        for (unsigned i = 0; i < core.size(); ++i) {
+            sat_solver->assert_expr(core[i]);
+        }
+        is_sat = sat_solver->check_sat(0, 0);
+        if (is_sat == l_true) {
+            IF_VERBOSE(0, verbose_stream() << "not a core\n";);
+        }        
+        
+    }
+
     void verify_assignment() {
         IF_VERBOSE(0, verbose_stream() << "verify assignment\n";);        
         ref<solver> sat_solver = mk_inc_sat_solver(m, m_params);
diff --git a/src/qe/qe.cpp b/src/qe/qe.cpp
index 17a1ccb1d..7275ff71f 100644
--- a/src/qe/qe.cpp
+++ b/src/qe/qe.cpp
@@ -1449,11 +1449,19 @@ namespace qe {
         
             m_solver.assert_expr(m_fml);
             if (assumption) m_solver.assert_expr(assumption);
-            bool is_sat = false;            
-            while (l_true == m_solver.check()) {
-                is_sat = true;
+            bool is_sat = false;   
+            lbool res = l_true;
+            while (res == l_true) {
+                res = m_solver.check();
+                if (res == l_true) is_sat = true;
                 final_check();
             }
+            if (res == l_undef) {
+                free_vars.append(num_vars, vars);
+                reset();
+                m_solver.pop(1);
+                return;
+            }
 
             if (!is_sat) {
                 fml = m.mk_false();
@@ -1484,12 +1492,13 @@ namespace qe {
                   );
 
             free_vars.append(m_free_vars);
-            SASSERT(!m_free_vars.empty() || m_solver.inconsistent());
+            if (!m_free_vars.empty() || m_solver.inconsistent()) {
 
-            if (m_fml.get() != m_subfml.get()) {
-                scoped_ptr<expr_replacer> rp = mk_default_expr_replacer(m);
-                rp->apply_substitution(to_app(m_subfml.get()), fml, m_fml);
-                fml = m_fml;
+                if (m_fml.get() != m_subfml.get()) {
+                    scoped_ptr<expr_replacer> rp = mk_default_expr_replacer(m);
+                    rp->apply_substitution(to_app(m_subfml.get()), fml, m_fml);
+                    fml = m_fml;
+                }
             }
             reset();
             m_solver.pop(1);
diff --git a/src/sat/sat_bceq.cpp b/src/sat/sat_bceq.cpp
index 65377caed..7ad0ec837 100644
--- a/src/sat/sat_bceq.cpp
+++ b/src/sat/sat_bceq.cpp
@@ -22,6 +22,7 @@ Revision History:
 #include"trace.h"
 #include"bit_vector.h"
 #include"map.h"
+#include"sat_elim_eqs.h"
 
 namespace sat {
     
@@ -54,7 +55,7 @@ namespace sat {
             }
         }
         bin_clauses bc;
-        m_solver.collect_bin_clauses(bc, false);
+        m_solver.collect_bin_clauses(bc, false); // exclude roots.
         literal lits[2];
         for (unsigned i = 0; i < bc.size(); ++i) {
             lits[0] = bc[i].first;
@@ -215,7 +216,7 @@ namespace sat {
             m_L.append(new_clauses);
             m_L_blits.append(new_blits);
         }
-        std::cout << "Number left after BCE: " << clauses.size() << "\n";
+        if (!clauses.empty()) std::cout << "Number left after BCE: " << clauses.size() << "\n";
         return clauses.empty();
     }
 
@@ -362,7 +363,13 @@ namespace sat {
             while (v != i) {
                 if (!m_solver.was_eliminated(v)) {
                     if (last_v != UINT_MAX) {
-                        check_equality(v, last_v);
+                        if (check_equality(v, last_v)) {
+                            // last_v was eliminated.
+                            
+                        }
+                        else {
+                            // TBD: refine partition.
+                        }
                     }
                     last_v = v;
                 }
@@ -371,7 +378,7 @@ namespace sat {
         }
     }
 
-    void bceq::check_equality(unsigned v1, unsigned v2) {
+    bool bceq::check_equality(unsigned v1, unsigned v2) {
         TRACE("sat", tout << "check: " << v1 << " = " << v2 << "\n";);
         uint64 val1 = m_rbits[v1];
         uint64 val2 = m_rbits[v2];
@@ -381,9 +388,9 @@ namespace sat {
             SASSERT(val1 == ~val2);
             l2.neg();
         }
-        if (is_equiv(l1, l2)) {
+        if (is_already_equiv(l1, l2)) {
             TRACE("sat", tout << "Already equivalent: " << l1 << " " << l2 << "\n";);
-            return;
+            return false;
         }
 
         literal lits[2];
@@ -397,13 +404,16 @@ namespace sat {
         }
         if (is_sat == l_false) {
             TRACE("sat", tout << "Found equivalent: " << l1 << " " << l2 << "\n";);
+            assert_equality(l1, l2);
         }
         else {
             TRACE("sat", tout << "Not equivalent: " << l1 << " " << l2 << "\n";);
+            // TBD: if is_sat == l_true, then refine partition.
         }
+        return is_sat == l_false;
     }
 
-    bool bceq::is_equiv(literal l1, literal l2) {
+    bool bceq::is_already_equiv(literal l1, literal l2) {
         watch_list const& w1 = m_solver.get_wlist(l1);
         bool found = false;
         for (unsigned i = 0; !found && i < w1.size(); ++i) {
@@ -420,6 +430,24 @@ namespace sat {
         return found;
     }
 
+    void bceq::assert_equality(literal l1, literal l2) {
+        if (l2.sign()) {
+            l1.neg();
+            l2.neg();
+        }
+        literal_vector roots;
+        bool_var_vector vars;
+        for (unsigned i = 0; i < m_solver.num_vars(); ++i) {
+            roots.push_back(literal(i, false));
+        }
+        roots[l2.var()] = l1;
+        vars.push_back(l2.var());
+        elim_eqs elim(m_solver);
+        for (unsigned i = 0; i < vars.size(); ++i) {
+            std::cout << "var: " << vars[i] << " root: " << roots[vars[i]] << "\n";
+        }
+        elim(roots, vars);
+    }
 
     void bceq::cleanup() {
         m_solver.del_clauses(m_bin_clauses.begin(), m_bin_clauses.end());
@@ -430,15 +458,23 @@ namespace sat {
     void bceq::operator()() {
         if (!m_solver.m_config.m_bcd) return;
         flet<bool> _disable_bcd(m_solver.m_config.m_bcd, false);
+        flet<bool> _disable_min(m_solver.m_config.m_minimize_core, false);
+        flet<bool> _disable_opt(m_solver.m_config.m_optimize_model, false);
+        flet<unsigned> _bound_maxc(m_solver.m_config.m_max_conflicts, 1500);
+
         use_list     ul;        
         solver       s(m_solver.m_params, 0);
+        s.m_config.m_bcd            = false;
+        s.m_config.m_minimize_core  = false;
+        s.m_config.m_optimize_model = false;
+        s.m_config.m_max_conflicts  = 1500;
         m_use_list = &ul;
         m_s = &s;
         ul.init(m_solver.num_vars());
         init();
         pure_decompose();
         post_decompose();
-        std::cout << "Decomposed set " << m_L.size() << "\n";
+        std::cout << "Decomposed set " << m_L.size() << " rest: " << m_R.size() << "\n";
 
         TRACE("sat",
               tout << "Decomposed set " << m_L.size() << "\n";
diff --git a/src/sat/sat_bceq.h b/src/sat/sat_bceq.h
index 5552fb255..0b05c45cd 100644
--- a/src/sat/sat_bceq.h
+++ b/src/sat/sat_bceq.h
@@ -65,8 +65,9 @@ namespace sat {
         uint64 eval_clause(clause const& cls) const;
         void verify_sweep();
         void extract_partition();
-        void check_equality(unsigned v1, unsigned v2);
-        bool is_equiv(literal l1, literal l2);
+        bool check_equality(unsigned v1, unsigned v2);
+        bool is_already_equiv(literal l1, literal l2);
+        void assert_equality(literal l1, literal l2);
     public:
         bceq(solver & s);
         void operator()();
diff --git a/src/sat/sat_config.cpp b/src/sat/sat_config.cpp
index d2a662b64..aff023b22 100644
--- a/src/sat/sat_config.cpp
+++ b/src/sat/sat_config.cpp
@@ -68,7 +68,10 @@ namespace sat {
         m_restart_factor  = p.restart_factor();
         
         m_random_freq     = p.random_freq();
-
+        m_random_seed     = p.random_seed();
+        if (m_random_seed == 0) 
+            m_random_seed = _p.get_uint("random_seed", 0);
+        
         m_burst_search    = p.burst_search();
         
         m_max_conflicts   = p.max_conflicts();
diff --git a/src/sat/sat_config.h b/src/sat/sat_config.h
index 021810f3d..61ab71605 100644
--- a/src/sat/sat_config.h
+++ b/src/sat/sat_config.h
@@ -53,6 +53,7 @@ namespace sat {
         unsigned           m_restart_initial;
         double             m_restart_factor; // for geometric case
         double             m_random_freq;
+        unsigned           m_random_seed;
         unsigned           m_burst_search;
         unsigned           m_max_conflicts;
 
diff --git a/src/sat/sat_mus.cpp b/src/sat/sat_mus.cpp
index a504a5fe2..c66f8ef6f 100644
--- a/src/sat/sat_mus.cpp
+++ b/src/sat/sat_mus.cpp
@@ -7,7 +7,7 @@ Module Name:
 
 Abstract:
    
-    Faster MUS extraction based on Belov et.al. HYB (Algorithm 3, 4)
+    Faster MUS extraction
 
 Author:
 
@@ -33,12 +33,27 @@ namespace sat {
         m_mus.reset();
         m_model.reset();
         m_best_value = 0;
+        m_max_restarts = 10;
+        m_restart = s.m_stats.m_restart;
     }
 
-    void mus::set_core() {        
-        m_core.append(m_mus);                
+    void mus::set_core() {   
+        m_mus.append(m_core);
         s.m_core.reset();
-        s.m_core.append(m_core);
+        s.m_core.append(m_mus);
+    }
+
+    void mus::update_model() {
+        double new_value = s.m_wsls.evaluate_model(s.m_model);
+        if (m_model.empty()) {
+            m_model.append(s.m_model);
+            m_best_value = new_value;
+        }
+        else if (m_best_value > new_value) {
+            m_model.reset();
+            m_model.append(s.m_model);
+            m_best_value = new_value;
+        }
     }
 
     lbool mus::operator()() {
@@ -56,6 +71,9 @@ namespace sat {
         TRACE("sat", tout << "old core: " << s.get_core() << "\n";);
         literal_vector& core = get_core();
         literal_vector& mus = m_mus;
+        if (core.size() > 64) {
+            return mus2();
+        }
         unsigned delta_time  = 0;
         unsigned core_miss = 0;
         while (!core.empty()) {
@@ -75,41 +93,31 @@ namespace sat {
 
             literal lit = core.back();
             core.pop_back();
-            unsigned sz = mus.size();
-            mus.append(core);
-            if (true || core_miss < 2) {
-                mus.push_back(~lit); // TBD: measure
+            lbool is_sat;
+            {
+                scoped_append _sa(mus, core);
+                if (true || core_miss < 2) {
+                    mus.push_back(~lit); // TBD: measure
+                }
+                is_sat = s.check(mus.size(), mus.c_ptr());
+                TRACE("sat", tout << "mus: " << mus << "\n";);
             }
-            lbool is_sat = s.check(mus.size(), mus.c_ptr());
-            TRACE("sat", tout << "mus: " << mus << "\n";);
             switch (is_sat) {
             case l_undef:
-                mus.resize(sz);
                 core.push_back(lit);
                 set_core();
                 return l_undef;
             case l_true: {
                 SASSERT(value_at(lit, s.get_model()) == l_false);
-                mus.resize(sz);
                 mus.push_back(lit);
+                update_model();
                 if (!core.empty()) {
                     // mr(); // TBD: measure
                 }
-                double new_value = s.m_wsls.evaluate_model(s.m_model);
-                if (m_model.empty()) {
-                    m_model.append(s.m_model);
-                    m_best_value = new_value;
-                }
-                else if (m_best_value > new_value) {
-                    m_model.reset();
-                    m_model.append(s.m_model);
-                    m_best_value = new_value;
-                }
                 break;
             }
             case l_false:
                 literal_vector const& new_core = s.get_core();
-                mus.resize(sz);
                 if (new_core.contains(~lit)) {
                     IF_VERBOSE(2, verbose_stream() << "miss core " << lit << "\n";);
                     ++core_miss;
@@ -141,27 +149,93 @@ namespace sat {
         IF_VERBOSE(2, verbose_stream() << "(sat.mus.new " << core << ")\n";);
         return l_true;
     }
+    
 
     // bisection search.
     lbool mus::mus2() {
-        literal_vector& core = get_core();
-        literal_vector& mus = m_mus;
-        while (true) {
+        literal_set core(get_core());
+        literal_set support;
+        lbool is_sat = qx(core, support, false);
+        s.m_core.reset();
+        s.m_core.append(core.to_vector());
+        IF_VERBOSE(2, verbose_stream() << "(sat.mus.new " << s.m_core << ")\n";);
+        return is_sat;
+    }
 
-#if 0
-            unsigned start = 0;
-            unsigned len = core.size();
-            SASSERT(start < len);
-            unsigned mid = (len-start+1)/2;
-            mus.append(mid, core.c_ptr() + start);
-            start = start + mid;
-#endif
+    lbool mus::qx(literal_set& assignment, literal_set& support, bool has_support) {
+        lbool is_sat = l_true;
+        if (s.m_stats.m_restart - m_restart > m_max_restarts) {
+            IF_VERBOSE(1, verbose_stream() << "restart budget exceeded\n";);
+            return l_true;
         }
-        return l_undef;
+        if (has_support) {
+            scoped_append _sa(m_mus, support.to_vector());
+            is_sat = s.check(m_mus.size(), m_mus.c_ptr());
+            switch (is_sat) {
+            case l_false: {
+                literal_set core(s.get_core());
+                support &= core;
+                assignment.reset();
+                return l_true;
+            }
+            case l_undef:
+                return l_undef;
+            case l_true:
+                update_model();
+                break;
+            default:
+                break;
+            }
+        }
+        if (assignment.size() == 1) {
+            return l_true;
+        }
+        literal_set assign2;
+        split(assignment, assign2);
+        support |= assignment;
+        is_sat = qx(assign2, support, !assignment.empty());        
+        unsplit(support, assignment);
+        if (is_sat != l_true) return is_sat;
+        support |= assign2;
+        is_sat = qx(assignment, support, !assign2.empty());
+        assignment |= assign2;
+        unsplit(support, assign2);
+        return is_sat;
+    }
+
+    void mus::unsplit(literal_set& A, literal_set& B) {
+        literal_set A1, B1;
+        literal_set::iterator it = A.begin(), end = A.end();
+        for (; it != end; ++it) {
+            if (B.contains(*it)) {
+                B1.insert(*it);
+            }
+            else {
+                A1.insert(*it);
+            }
+        }
+        A = A1;
+        B = B1;
+    }
+
+    void mus::split(literal_set& lits1, literal_set& lits2) {
+        unsigned half = lits1.size()/2;
+        literal_set lits3;
+        literal_set::iterator it = lits1.begin(), end = lits1.end();
+        for (unsigned i = 0; it != end; ++it, ++i) {
+            if (i < half) {
+                lits3.insert(*it);
+            }
+            else {
+                lits2.insert(*it);
+            }
+        }
+        lits1 = lits3;
     }
 
     literal_vector& mus::get_core() {
         m_core.reset();
+        m_mus.reset();
         literal_vector& core = m_core;
         core.append(s.get_core());        
         for (unsigned i = 0; i < core.size(); ++i) {
@@ -175,6 +249,11 @@ namespace sat {
         return core;
     }
 
+    void mus::verify_core(literal_vector const& core) {
+        lbool is_sat = s.check(core.size(), core.c_ptr());
+        IF_VERBOSE(3, verbose_stream() << "core verification: " << is_sat << " " << core << "\n";);
+    }
+
     void mus::mr() {
         sls sls(s);
         literal_vector tabu;
diff --git a/src/sat/sat_mus.h b/src/sat/sat_mus.h
index ed7b8b13e..944cceffb 100644
--- a/src/sat/sat_mus.h
+++ b/src/sat/sat_mus.h
@@ -26,6 +26,8 @@ namespace sat {
         bool           m_is_active;
         model          m_model;       // model obtained during minimal unsat core
         double         m_best_value;
+        unsigned       m_restart;
+        unsigned       m_max_restarts;
 
 
         solver& s;
@@ -38,10 +40,30 @@ namespace sat {
     private:
         lbool mus1();
         lbool mus2();
+        lbool qx(literal_set& assignment, literal_set& support, bool has_support);
         void mr();
         void reset();
         void set_core();
+        void update_model();
         literal_vector & get_core();
+        void verify_core(literal_vector const& lits);
+        void split(literal_set& src, literal_set& dst);
+        void intersect(literal_set& dst, literal_set const& src);
+        void unsplit(literal_set& A, literal_set& B);
+        class scoped_append {
+            unsigned m_size;
+            literal_vector& m_lits;
+        public:
+            scoped_append(literal_vector& lits, literal_vector const& other):
+                m_size(lits.size()),
+                m_lits(lits) {
+                m_lits.append(other);
+            }
+            ~scoped_append() {
+                m_lits.resize(m_size);
+            }
+                
+        };
     };
 
 };
diff --git a/src/sat/sat_params.pyg b/src/sat/sat_params.pyg
index 1e2551740..c5ac97b4e 100644
--- a/src/sat/sat_params.pyg
+++ b/src/sat/sat_params.pyg
@@ -9,6 +9,7 @@ def_module_params('sat',
                           ('restart.initial', UINT, 100, 'initial restart (number of conflicts)'),
                           ('restart.factor', DOUBLE, 1.5, 'restart increment factor for geometric strategy'),
                           ('random_freq', DOUBLE, 0.01, 'frequency of random case splits'),
+                          ('random_seed', UINT, 0, 'random seed'),
                           ('burst_search', UINT, 100, 'number of conflicts before first global simplification'),
                           ('max_conflicts', UINT, UINT_MAX, 'maximum number of conflicts'),
                           ('gc', SYMBOL, 'glue_psm', 'garbage collection strategy: psm, glue, glue_psm, dyn_psm'),
diff --git a/src/sat/sat_simplifier.cpp b/src/sat/sat_simplifier.cpp
index 937c7735f..285df1e78 100644
--- a/src/sat/sat_simplifier.cpp
+++ b/src/sat/sat_simplifier.cpp
@@ -21,7 +21,6 @@ Revision History:
 #include"sat_simplifier.h"
 #include"sat_simplifier_params.hpp"
 #include"sat_solver.h"
-#include"sat_bceq.h"
 #include"stopwatch.h"
 #include"trace.h"
 
@@ -138,8 +137,10 @@ namespace sat {
             return;
         if (!m_subsumption && !m_elim_blocked_clauses && !m_resolution)
             return;
+
         CASSERT("sat_solver", s.check_invariant());
         TRACE("before_simplifier", s.display(tout););
+
         s.m_cleaner(true);
         m_last_sub_trail_sz = s.m_trail.size();
         TRACE("after_cleanup", s.display(tout););
@@ -157,13 +158,6 @@ namespace sat {
         if (!learned && (m_elim_blocked_clauses || m_elim_blocked_clauses_at == m_num_calls))
             elim_blocked_clauses();
 
-#if 1
-        // experiment is disabled.
-        if (!learned) { // && m_equality_inference
-            bceq bc(s);
-            bc();
-        }
-#endif
 
         if (!learned)
             m_num_calls++;
@@ -188,23 +182,21 @@ namespace sat {
 
         bool vars_eliminated = m_num_elim_vars > old_num_elim_vars;
 
-        if (!m_need_cleanup) {
+        if (m_need_cleanup) {
+            TRACE("after_simplifier", tout << "cleanning watches...\n";);
+            cleanup_watches();
+            cleanup_clauses(s.m_learned, true, vars_eliminated,  learned_in_use_lists);
+            cleanup_clauses(s.m_clauses, false, vars_eliminated, true);
+        }
+        else {
             TRACE("after_simplifier", tout << "skipping cleanup...\n";);
             if (vars_eliminated) {
                 // must remove learned clauses with eliminated variables
                 cleanup_clauses(s.m_learned, true, true, learned_in_use_lists);
             }
-            CASSERT("sat_solver", s.check_invariant());
-            TRACE("after_simplifier", s.display(tout); tout << "model_converter:\n"; s.m_mc.display(tout););
-            free_memory();
-            return;
         }
-        TRACE("after_simplifier", tout << "cleanning watches...\n";);
-        cleanup_watches();
-        cleanup_clauses(s.m_learned, true, vars_eliminated,  learned_in_use_lists);
-        cleanup_clauses(s.m_clauses, false, vars_eliminated, true);
-        TRACE("after_simplifier", s.display(tout); tout << "model_converter:\n"; s.m_mc.display(tout););
         CASSERT("sat_solver", s.check_invariant());
+        TRACE("after_simplifier", s.display(tout); tout << "model_converter:\n"; s.m_mc.display(tout););
         free_memory();
     }
 
@@ -926,11 +918,11 @@ namespace sat {
 
         void process(literal l) {
             TRACE("blocked_clause", tout << "processing: " << l << "\n";);
-            if (s.is_external(l.var()) || s.was_eliminated(l.var())) {
-                return;
-            }
             model_converter::entry * new_entry = 0;
+            if (s.is_external(l.var()) || s.was_eliminated(l.var())) 
+                return;
             {
+
                 m_to_remove.reset();
                 {
                     clause_use_list & occs = s.m_use_list.get(l);
@@ -1186,7 +1178,6 @@ namespace sat {
                 continue;
             m_visited[l2.index()] = false;
         }
-
         return res;
     }
 
@@ -1351,6 +1342,7 @@ namespace sat {
         }
         TRACE("resolution", tout << "found var to eliminate, before: " << before_clauses << " after: " << after_clauses << "\n";);
 
+        
         // eliminate variable
         model_converter::entry & mc_entry = s.m_mc.mk(model_converter::ELIM_VAR, v);
         save_clauses(mc_entry, m_pos_cls);
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index d97ebed46..a2d39d3ea 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -49,7 +49,7 @@ namespace sat {
         m_qhead(0),
         m_scope_lvl(0),
         m_params(p) {
-        m_config.updt_params(p);
+        updt_params(p);
         m_conflicts_since_gc      = 0;
         m_conflicts               = 0;
         m_next_simplify           = 0;
@@ -483,7 +483,6 @@ namespace sat {
     void solver::set_conflict(justification c, literal not_l) {
         if (m_inconsistent)
             return;
-        TRACE("sat", tout << "conflict: " << not_l << "\n";);
         m_inconsistent = true;
         m_conflict = c;
         m_not_l    = not_l;
@@ -960,7 +959,11 @@ namespace sat {
         m_stopwatch.start();
         m_core.reset();
         TRACE("sat", display(tout););
-
+        
+        if (m_config.m_bcd) {
+            bceq bc(*this);
+            bc();
+        }
     }
 
     /**
@@ -1737,11 +1740,10 @@ namespace sat {
             // TBD: 
             // apply optional clause minimization by detecting subsumed literals.
             // initial experiment suggests it has no effect.
-
             m_mus(); // ignore return value on cancelation.
             m_model.reset();
             m_model.append(m_mus.get_model());            
-            m_model_is_current = true;
+            m_model_is_current = !m_model.empty();
         }
     }
 
@@ -2356,7 +2358,7 @@ namespace sat {
         m_asymm_branch.updt_params(p);
         m_probing.updt_params(p);
         m_scc.updt_params(p);
-        m_rand.set_seed(p.get_uint("random_seed", 0));
+        m_rand.set_seed(m_config.m_random_seed);
     }
 
     void solver::collect_param_descrs(param_descrs & d) {
diff --git a/src/sat/sat_types.h b/src/sat/sat_types.h
index db8de94a9..075c88fa1 100644
--- a/src/sat/sat_types.h
+++ b/src/sat/sat_types.h
@@ -160,6 +160,12 @@ namespace sat {
             m_in_set[v] = true; 
             m_set.push_back(v); 
         }
+
+        uint_set& operator=(uint_set const& other) {
+            m_in_set = other.m_in_set;
+            m_set = other.m_set;
+            return *this;
+        }
         
         bool contains(unsigned v) const { 
             return v < m_in_set.size() && m_in_set[v] != 0; 
@@ -177,10 +183,31 @@ namespace sat {
             m_in_set[v] = false; 
             return v; 
         }
+        unsigned size() const { return m_set.size(); }
         iterator begin() const { return m_set.begin(); }
         iterator end() const { return m_set.end(); }
         void reset() { m_set.reset(); m_in_set.reset(); }
         void cleanup() { m_set.finalize(); m_in_set.finalize(); }
+        uint_set& operator&=(uint_set const& other) {
+            unsigned j = 0;
+            for (unsigned i = 0; i < m_set.size(); ++i) {
+                if (other.contains(m_set[i])) {
+                    m_set[j] = m_set[i];
+                    ++j;
+                }
+                else {
+                    m_in_set[m_set[i]] = false;
+                }
+            }
+            m_set.resize(j);
+            return *this;
+        }
+        uint_set& operator|=(uint_set const& other) {
+            for (unsigned i = 0; i < other.m_set.size(); ++i) {
+                insert(other.m_set[i]);
+            }
+            return *this;
+        }
     };
 
     typedef uint_set bool_var_set;
@@ -188,11 +215,44 @@ namespace sat {
     class literal_set {
         uint_set m_set;
     public:
+        literal_set(literal_vector const& v) {
+            for (unsigned i = 0; i < v.size(); ++i) insert(v[i]);
+        }
+        literal_set() {}
+        literal_vector to_vector() const {
+            literal_vector result;
+            iterator it = begin(), e = end();
+            for (; it != e; ++it) {
+                result.push_back(*it);
+            }
+            return result;
+        }
         void insert(literal l) { m_set.insert(l.index()); }
         bool contains(literal l) const { return m_set.contains(l.index()); }
         bool empty() const { return m_set.empty(); }
+        unsigned size() const { return m_set.size(); }
         void reset() { m_set.reset(); }
         void cleanup() { m_set.cleanup(); }
+        class iterator {
+            uint_set::iterator m_it;
+        public:
+            iterator(uint_set::iterator it):m_it(it) {}
+            literal operator*() const { return to_literal(*m_it); }
+            iterator& operator++() { ++m_it; return *this; }
+            iterator operator++(int) { iterator tmp = *this; ++m_it; return tmp; }
+            bool operator==(iterator const& it) const { return m_it == it.m_it; }
+            bool operator!=(iterator const& it) const { return m_it != it.m_it; }
+        };
+        iterator begin() const { return iterator(m_set.begin()); }
+        iterator end() const { return iterator(m_set.end()); }
+        literal_set& operator&=(literal_set const& other) {
+            m_set &= other.m_set;
+            return *this;
+        }
+        literal_set& operator|=(literal_set const& other) {
+            m_set |= other.m_set;
+            return *this;
+        }
     };
     
     struct mem_stat {
diff --git a/src/smt/smt_context.cpp b/src/smt/smt_context.cpp
index f68df30ab..6b6223385 100644
--- a/src/smt/smt_context.cpp
+++ b/src/smt/smt_context.cpp
@@ -1616,6 +1616,8 @@ namespace smt {
             unsigned qhead = m_qhead;
             if (!bcp())
                 return false;
+            if (m_cancel_flag) 
+                return true;
             SASSERT(!inconsistent());
             propagate_relevancy(qhead);
             if (inconsistent()) 
@@ -3950,7 +3952,7 @@ namespace smt {
               m_fingerprints.display(tout); 
               );
         failure fl = get_last_search_failure();
-        if (fl == TIMEOUT || fl == MEMOUT || fl == CANCELED || fl == NUM_CONFLICTS || fl == THEORY) {
+        if (fl == TIMEOUT || fl == MEMOUT || fl == CANCELED || fl == NUM_CONFLICTS) {
             // don't generate model.
             return;
         }
diff --git a/src/smt/theory_arith_core.h b/src/smt/theory_arith_core.h
index 7414eda83..89ce99524 100644
--- a/src/smt/theory_arith_core.h
+++ b/src/smt/theory_arith_core.h
@@ -1274,8 +1274,10 @@ namespace smt {
             }
         }
         while (m_final_check_idx != old_idx);
-        if (result == FC_DONE && m_found_unsupported_op)
+        if (result == FC_DONE && m_found_unsupported_op) {
+            TRACE("arith", tout << "Found unsupported operation\n";);
             result = FC_GIVEUP;
+        }
         return result;
     }
 
diff --git a/src/smt/theory_arith_int.h b/src/smt/theory_arith_int.h
index 4b5388062..b600dd3c0 100644
--- a/src/smt/theory_arith_int.h
+++ b/src/smt/theory_arith_int.h
@@ -1299,8 +1299,10 @@ namespace smt {
               }
               tout << "max: " << max << ", min: " << min << "\n";);
 
-        if (m_params.m_arith_ignore_int)
+        if (m_params.m_arith_ignore_int) {
+            TRACE("arith", tout << "Ignore int: give up\n";);
             return FC_GIVEUP;
+        }
 
         if (!gcd_test())
             return FC_CONTINUE;
diff --git a/src/smt/theory_arith_nl.h b/src/smt/theory_arith_nl.h
index d02c9e540..6a7017a29 100644
--- a/src/smt/theory_arith_nl.h
+++ b/src/smt/theory_arith_nl.h
@@ -2314,13 +2314,15 @@ namespace smt {
             return FC_DONE;
         }
 
-        if (!m_params.m_nl_arith)
+        if (!m_params.m_nl_arith) {
+            TRACE("non_linear", tout << "Non-linear is not enabled\n";);
             return FC_GIVEUP;
+        }
 
         TRACE("process_non_linear", display(tout););
 
         if (m_nl_rounds > m_params.m_nl_arith_rounds) {
-            TRACE("non_linear", tout << "GIVE UP non linear problem...\n";);
+            TRACE("non_linear", tout << "GIVEUP non linear problem...\n";);
             IF_VERBOSE(3, verbose_stream() << "Max. non linear arithmetic rounds. Increase threshold using NL_ARITH_ROUNDS=<limit>\n";);
             return FC_GIVEUP;
         }
diff --git a/src/smt/theory_diff_logic_def.h b/src/smt/theory_diff_logic_def.h
index 85f7f948a..b1f3483a9 100644
--- a/src/smt/theory_diff_logic_def.h
+++ b/src/smt/theory_diff_logic_def.h
@@ -1066,11 +1066,8 @@ template<typename Ext>
 void theory_diff_logic<Ext>::get_eq_antecedents(
     theory_var v1, theory_var v2, unsigned timestamp, conflict_resolution & cr) {
     imp_functor functor(cr);
-    bool r;
-    r = m_graph.find_shortest_zero_edge_path(v1, v2, timestamp, functor);
-    SASSERT(r);
-    r = m_graph.find_shortest_zero_edge_path(v2, v1, timestamp, functor);
-    SASSERT(r);
+    VERIFY(m_graph.find_shortest_zero_edge_path(v1, v2, timestamp, functor));
+    VERIFY(m_graph.find_shortest_zero_edge_path(v2, v1, timestamp, functor));
 }
 
 template<typename Ext>
diff --git a/src/util/bit_vector.cpp b/src/util/bit_vector.cpp
index b8cbdade2..f0e9e9c67 100644
--- a/src/util/bit_vector.cpp
+++ b/src/util/bit_vector.cpp
@@ -138,9 +138,8 @@ bool bit_vector::operator==(bit_vector const & source) const {
 bit_vector & bit_vector::operator|=(bit_vector const & source) {
     if (size() < source.size())
         resize(source.size(), false);
-    unsigned n1 = num_words();
     unsigned n2 = source.num_words();
-    SASSERT(n2 <= n1);
+    SASSERT(n2 <= num_words());
     unsigned bit_rest = source.m_num_bits % 32;
     if (bit_rest == 0) {
         unsigned i = 0;
diff --git a/src/util/cmd_context_types.h b/src/util/cmd_context_types.h
index b0a0226e8..e334dc0d2 100644
--- a/src/util/cmd_context_types.h
+++ b/src/util/cmd_context_types.h
@@ -55,12 +55,12 @@ class cmd_exception : public default_exception {
     }
 public:
     cmd_exception(char const * msg):default_exception(msg), m_line(-1), m_pos(-1) {}
-    cmd_exception(std::string const & msg):default_exception(msg.c_str()), m_line(-1), m_pos(-1) {}
-    cmd_exception(std::string const & msg, int line, int pos):default_exception(msg.c_str()), m_line(line), m_pos(pos) {}
+    cmd_exception(std::string const & msg):default_exception(msg), m_line(-1), m_pos(-1) {}
+    cmd_exception(std::string const & msg, int line, int pos):default_exception(msg), m_line(line), m_pos(pos) {}
     cmd_exception(char const * msg, symbol const & s): 
-        default_exception(compose(msg,s).c_str()),m_line(-1),m_pos(-1) {}
+        default_exception(compose(msg,s)),m_line(-1),m_pos(-1) {}
     cmd_exception(char const * msg, symbol const & s, int line, int pos): 
-        default_exception(compose(msg,s).c_str()),m_line(line),m_pos(pos) {}
+        default_exception(compose(msg,s)),m_line(line),m_pos(pos) {}
 
     bool has_pos() const { return m_line >= 0; }
     int line() const { SASSERT(has_pos()); return m_line; }
diff --git a/src/util/mpf.cpp b/src/util/mpf.cpp
index 8cb6ed4fc..f5785c072 100644
--- a/src/util/mpf.cpp
+++ b/src/util/mpf.cpp
@@ -120,7 +120,8 @@ void mpf_manager::set(mpf & o, unsigned ebits, unsigned sbits, double value) {
     // double === mpf(11, 53)
     COMPILE_TIME_ASSERT(sizeof(double) == 8);
 
-    uint64 raw = *reinterpret_cast<uint64*>(&value);
+    uint64 raw;
+    memcpy(&raw, &value, sizeof(double));
     bool sign = (raw >> 63) != 0;
     int64 e =  ((raw & 0x7FF0000000000000ull) >> 52) - 1023;
     uint64 s = raw & 0x000FFFFFFFFFFFFFull;
@@ -155,7 +156,8 @@ void mpf_manager::set(mpf & o, unsigned ebits, unsigned sbits, float value) {
     // single === mpf(8, 24)
     COMPILE_TIME_ASSERT(sizeof(float) == 4);
 
-    unsigned int raw = *reinterpret_cast<unsigned int*>(&value);
+    unsigned int raw;
+    memcpy(&raw, &value, sizeof(float));
     bool sign = (raw >> 31) != 0;
     signed int e = ((raw & 0x7F800000) >> 23) - 127;
     unsigned int s = raw & 0x007FFFFF;
@@ -1288,7 +1290,9 @@ double mpf_manager::to_double(mpf const & x) {
     if (x.sign) 
         raw = raw | 0x8000000000000000ull;
 
-    return *reinterpret_cast<double*>(&raw);
+    double ret;
+    memcpy(&ret, &raw, sizeof(double));
+    return ret;
 }
 
 float mpf_manager::to_float(mpf const & x) {
@@ -1318,7 +1322,9 @@ float mpf_manager::to_float(mpf const & x) {
     if (x.sign)
         raw = raw | 0x80000000;
 
-    return *reinterpret_cast<float*>(&raw);
+    float ret;
+    memcpy(&ret, &raw, sizeof(float));
+    return ret;
 }
 
 bool mpf_manager::is_nan(mpf const & x) {
@@ -1679,7 +1685,7 @@ void mpf_manager::round(mpf_rounding_mode rm, mpf & o) {
     TRACE("mpf_dbg", tout << "OVF2 = " << OVF2 << std::endl;);
     TRACE("mpf_dbg", tout << "o_has_max_exp = " << o_has_max_exp << std::endl;);
 
-    if (!OVFen && SIGovf && o_has_max_exp)
+    if (!OVFen && OVF2)
         mk_round_inf(rm, o);
     else {        
         const mpz & p = m_powers2(o.sbits-1);
diff --git a/src/util/mpff.cpp b/src/util/mpff.cpp
index 892a7fe24..7678a051e 100644
--- a/src/util/mpff.cpp
+++ b/src/util/mpff.cpp
@@ -43,8 +43,7 @@ mpff_manager::mpff_manager(unsigned prec, unsigned initial_capacity) {
     for (unsigned i = 0; i < MPFF_NUM_BUFFERS; i++)
         m_buffers[i].resize(2 * prec, 0);
     // Reserve space for zero
-    unsigned zero_sig_idx = m_id_gen.mk();
-    SASSERT(zero_sig_idx == 0);
+    VERIFY(m_id_gen.mk() == 0);
     set(m_one, 1);
 }
 
diff --git a/src/util/mpfx.cpp b/src/util/mpfx.cpp
index cf6f8338f..c0b3a1936 100644
--- a/src/util/mpfx.cpp
+++ b/src/util/mpfx.cpp
@@ -38,8 +38,7 @@ mpfx_manager::mpfx_manager(unsigned int_sz, unsigned frac_sz, unsigned initial_c
     m_buffer0.resize(2*m_total_sz, 0);
     m_buffer1.resize(2*m_total_sz, 0);
     m_buffer2.resize(2*m_total_sz, 0);
-    unsigned zero_sig_idx = m_id_gen.mk();
-    SASSERT(zero_sig_idx == 0);
+    VERIFY(m_id_gen.mk() == 0);
     set(m_one, 1);
 }
 
diff --git a/src/util/mpq.cpp b/src/util/mpq.cpp
index eda937029..df4d207a6 100644
--- a/src/util/mpq.cpp
+++ b/src/util/mpq.cpp
@@ -235,6 +235,9 @@ void mpq_manager<SYNCH>::set(mpq & a, char const * val) {
                     SASSERT(str[0] - '0' <= 9);
                     exp = (10*exp) + (str[0] - '0');
                 }
+                else if ('/' == str[0]) {
+                    throw default_exception("mixing rational/scientific notation");
+                }
                 TRACE("mpq_set", tout << "[exp]: " << exp << ", str[0]: " << (str[0] - '0') << std::endl;);
                 ++str;
             }
diff --git a/src/util/util.h b/src/util/util.h
index eb24ece13..cbc19b759 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -24,9 +24,6 @@ Revision History:
 #include<iostream>
 #include<climits>
 #include<limits>
-#ifdef _MSC_VER
-#include<intrin.h>
-#endif
 
 #ifndef SIZE_MAX
 #define SIZE_MAX std::numeric_limits<std::size_t>::max()
@@ -99,9 +96,7 @@ COMPILE_TIME_ASSERT(sizeof(unsigned) == 4);
 
 // Return the number of 1 bits in v.
 static inline unsigned get_num_1bits(unsigned v) {
-#ifdef _MSC_VER
-    return __popcnt(v);
-#elif defined(__GNUC__)
+#ifdef __GNUC__
     return __builtin_popcount(v);
 #else
 #ifdef Z3DEBUG