diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index 9cf13afe4..e6fa15a4c 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -2917,6 +2917,7 @@ namespace sat {
         ++max_weight;
 
         out << "p wcnf " << num_vars() << " " << num_clauses() + sz << " " << max_weight << "\n";
+        out << "c soft " << sz << "\n";
 
         for (unsigned i = 0; i < m_trail.size(); i++) {
             out << max_weight << " " << dimacs_lit(m_trail[i]) << " 0\n";
@@ -2940,9 +2941,9 @@ namespace sat {
             clause_vector::const_iterator end = cs.end();
             for (; it != end; ++it) {
                 clause const & c = *(*it);
-                unsigned sz = c.size();
+                unsigned clsz = c.size();
                 out << max_weight << " ";
-                for (unsigned j = 0; j < sz; j++)
+                for (unsigned j = 0; j < clsz; j++)
                     out << dimacs_lit(c[j]) << " ";
                 out << "0\n";
             }
@@ -2950,6 +2951,7 @@ namespace sat {
         for (unsigned i = 0; i < sz; ++i) {
             out << weights[i] << " " << lits[i] << " 0\n";
         }
+        out.flush();
     }
 
 
diff --git a/src/sat/sat_solver/inc_sat_solver.cpp b/src/sat/sat_solver/inc_sat_solver.cpp
index e56abc50c..e3a220cd2 100644
--- a/src/sat/sat_solver/inc_sat_solver.cpp
+++ b/src/sat/sat_solver/inc_sat_solver.cpp
@@ -115,10 +115,18 @@ public:
         if (weights != 0) {
             for (unsigned i = 0; i < sz; ++i) m_weights.push_back(weights[i]);
         }
+        init_preprocess();
         m_solver.pop_to_base_level();
         dep2asm_t dep2asm;
+        expr_ref_vector asms(m);
+        for (unsigned i = 0; i < sz; ++i) {
+            expr_ref a(m.mk_fresh_const("s", m.mk_bool_sort()), m);
+            expr_ref fml(m.mk_implies(a, assumptions[i]), m);
+            assert_expr(fml);
+            asms.push_back(a);
+        }
         VERIFY(l_true == internalize_formulas());
-        VERIFY(l_true == internalize_assumptions(sz, assumptions, dep2asm));
+        VERIFY(l_true == internalize_assumptions(sz, asms.c_ptr(), dep2asm));
         svector<unsigned> nweights;
         for (unsigned i = 0; i < m_asms.size(); ++i) {
             nweights.push_back((unsigned) m_weights[i]);
diff --git a/src/sat/tactic/goal2sat.cpp b/src/sat/tactic/goal2sat.cpp
index 136921914..742a4fb1d 100644
--- a/src/sat/tactic/goal2sat.cpp
+++ b/src/sat/tactic/goal2sat.cpp
@@ -174,6 +174,7 @@ struct goal2sat::imp {
         switch (to_app(t)->get_decl_kind()) {
         case OP_NOT:
         case OP_OR:
+        case OP_AND:
         case OP_IFF:
             m_frame_stack.push_back(frame(to_app(t), root, sign, 0));
             return false;
@@ -185,7 +186,6 @@ struct goal2sat::imp {
             }
             convert_atom(t, root, sign);
             return true;
-        case OP_AND:
         case OP_XOR:
         case OP_IMPLIES:
         case OP_DISTINCT: {
@@ -215,8 +215,8 @@ struct goal2sat::imp {
             }
             else {
                 mk_clause(m_result_stack.size(), m_result_stack.c_ptr());
-                m_result_stack.reset();
             }
+            m_result_stack.reset();
         }
         else {
             SASSERT(num <= m_result_stack.size());
@@ -240,6 +240,48 @@ struct goal2sat::imp {
         }
     }
 
+    void convert_and(app * t, bool root, bool sign) {
+        TRACE("goal2sat", tout << "convert_and:\n" << mk_ismt2_pp(t, m) << "\n";);
+        unsigned num = t->get_num_args();
+        if (root) {
+            if (sign) {
+                for (unsigned i = 0; i < num; ++i) {
+                    m_result_stack[i].neg();
+                }                
+            }
+            else {
+                for (unsigned i = 0; i < num; ++i) {
+                    mk_clause(m_result_stack[i]);
+                }
+            }
+            m_result_stack.reset();
+        }
+        else {
+            SASSERT(num <= m_result_stack.size());
+            sat::bool_var k = m_solver.mk_var();
+            sat::literal  l(k, false);
+            m_cache.insert(t, l);
+            // l => /\ lits
+            sat::literal * lits = m_result_stack.end() - num;
+            for (unsigned i = 0; i < num; i++) {
+                mk_clause(~l, lits[i]);
+            }
+            // /\ lits => l
+            for (unsigned i = 0; i < num; ++i) {
+                m_result_stack[m_result_stack.size() - num + i].neg();
+            }
+            m_result_stack.push_back(l);
+            lits = m_result_stack.end() - num - 1;
+            mk_clause(num+1, lits);
+            unsigned old_sz = m_result_stack.size() - num - 1;
+            m_result_stack.shrink(old_sz);
+            if (sign)
+                l.neg();
+            m_result_stack.push_back(l);
+        }
+    }
+
+
     void convert_ite(app * n, bool root, bool sign) {
         unsigned sz = m_result_stack.size();
         SASSERT(sz >= 3);
@@ -316,6 +358,9 @@ struct goal2sat::imp {
         case OP_OR:
             convert_or(t, root, sign);
             break;
+        case OP_AND:
+            convert_and(t, root, sign);
+            break;
         case OP_ITE:
             convert_ite(t, root, sign);
             break;
@@ -456,7 +501,6 @@ struct unsupported_bool_proc {
     void operator()(app * n) { 
         if (n->get_family_id() == m.get_basic_family_id()) {
             switch (n->get_decl_kind()) {
-            case OP_AND:
             case OP_XOR:
             case OP_IMPLIES:
             case OP_DISTINCT: