diff --git a/scripts/mk_project.py b/scripts/mk_project.py
index 6d739e4e2..48475ff74 100644
--- a/scripts/mk_project.py
+++ b/scripts/mk_project.py
@@ -29,7 +29,7 @@ def init_project_def():
     add_lib('sat', ['util', 'dd', 'grobner'])    
     add_lib('nlsat', ['polynomial', 'sat'])
     add_lib('smt_params', ['ast', 'params'], 'smt/params')
-    add_lib('lp', ['util', 'nlsat', 'grobner', 'interval'], 'math/lp')
+    add_lib('lp', ['util', 'nlsat', 'grobner', 'interval', 'smt_params'], 'math/lp')
     add_lib('rewriter', ['ast', 'polynomial', 'automata', 'params'], 'ast/rewriter')
     add_lib('macros', ['rewriter'], 'ast/macros')
     add_lib('normal_forms', ['rewriter'], 'ast/normal_forms')
diff --git a/src/sat/smt/array_axioms.cpp b/src/sat/smt/array_axioms.cpp
index b6b310b34..3d1853797 100644
--- a/src/sat/smt/array_axioms.cpp
+++ b/src/sat/smt/array_axioms.cpp
@@ -22,24 +22,37 @@ Author:
 
 namespace array {
 
+    struct solver::reset_new : trail {
+        solver& s;
+        unsigned m_idx;
+        reset_new(solver& s, unsigned idx) : s(s), m_idx(idx) {}
+        void undo() override {
+            s.m_axiom_trail[m_idx].set_new();
+        }
+    };
+
     void solver::push_axiom(axiom_record const& r) { 
         unsigned idx = m_axiom_trail.size();
         m_axiom_trail.push_back(r); 
         TRACE("array", display(tout, r) << " " << m_axioms.contains(idx) << "\n";);
         if (m_axioms.contains(idx))
             m_axiom_trail.pop_back();
-        else
+        else {
+            m_axioms.insert(idx);
             ctx.push(push_back_vector<svector<axiom_record>>(m_axiom_trail));
+            ctx.push(insert_map<axiom_table_t, unsigned>(m_axioms, idx));
+        }
     }
 
     bool solver::propagate_axiom(unsigned idx) {        
-        if (!m_axioms.contains(idx)) {
-            m_axioms.insert(idx);
-            ctx.push(insert_map<axiom_table_t, unsigned>(m_axioms, idx));
-        }
-        else if (!m_axiom_trail[idx].is_delayed())
+        if (is_applied(idx))
             return false;
-        return assert_axiom(idx);
+        bool st = assert_axiom(idx);
+        if (!is_delayed(idx)) {
+            ctx.push(reset_new(*this, idx));
+            set_applied(idx);
+        }
+        return st;
     }
 
     bool solver::assert_axiom(unsigned idx) {
@@ -79,14 +92,6 @@ namespace array {
             return false;                
     }
 
-    struct solver::set_delay_bit : trail {
-        solver& s;
-        unsigned m_idx;
-        set_delay_bit(solver& s, unsigned idx) : s(s), m_idx(idx) {}
-        void undo() override {
-            s.m_axiom_trail[m_idx].m_delayed = false;
-        }
-    };
 
     bool solver::is_relevant(axiom_record const& r) const {
         return true;
@@ -117,13 +122,13 @@ namespace array {
         SASSERT(can_beta_reduce(r.n));
         TRACE("array", display(tout << "select-axiom: ", r) << "\n";);
 
-        if (get_config().m_array_delay_exp_axiom && r.select->get_arg(0)->get_root() != r.n->get_root() && !r.m_delayed && m_enable_delay) {
+        if (get_config().m_array_delay_exp_axiom && r.select->get_arg(0)->get_root() != r.n->get_root() && !r.is_delayed() && m_enable_delay) {
             IF_VERBOSE(11, verbose_stream() << "delay: " << mk_bounded_pp(child, m) << " " << mk_bounded_pp(select, m) << "\n");
-            ctx.push(set_delay_bit(*this, idx));
-            r.m_delayed = true;
+            ctx.push(reset_new(*this, idx));
+            r.set_delayed();
             return false;
         }
-        r.m_delayed = false;
+        r.set_applied();
         if (a.is_const(child))
             return assert_select_const_axiom(select, to_app(child));
         else if (a.is_as_array(child))
@@ -165,7 +170,6 @@ namespace array {
      * where i = (i_1, ..., i_n), j = (j_1, .., j_n), k in 1..n
      */
     bool solver::assert_select_store_axiom(app* select, app* store) {
-        ++m_stats.m_num_select_store_axiom;
         SASSERT(a.is_store(store));
         SASSERT(a.is_select(select));
         SASSERT(store->get_num_args() == 1 + select->get_num_args());
@@ -174,11 +178,17 @@ namespace array {
         sel1_args.push_back(store);
         sel2_args.push_back(store->get_arg(0));
 
+        bool has_diff = false;
+        for (unsigned i = 1; i < num_args; i++) 
+            has_diff |= expr2enode(select->get_arg(i))->get_root() != expr2enode(store->get_arg(i))->get_root();
+        if (!has_diff)
+            return false;
+        
         for (unsigned i = 1; i < num_args; i++) {
             sel1_args.push_back(select->get_arg(i));
             sel2_args.push_back(select->get_arg(i));
         }
-
+   
         expr_ref sel1(a.mk_select(sel1_args), m);
         expr_ref sel2(a.mk_select(sel2_args), m);
         expr_ref sel_eq_e(m.mk_eq(sel1, sel2), m);
@@ -194,7 +204,13 @@ namespace array {
         sat::literal sel_eq = mk_literal(sel_eq_e);
         if (s().value(sel_eq) == l_true)
             return false;
-        
+
+#if 0
+        static unsigned count = 0;
+        ++count;
+        std::cout << count << " " << sel_eq << "\n";
+#endif
+
         bool new_prop = false;
         for (unsigned i = 1; i < num_args; i++) {
             expr* idx1 = store->get_arg(i);
@@ -212,6 +228,7 @@ namespace array {
             if (add_clause(idx_eq, sel_eq))
                 new_prop = true;
         }
+        ++m_stats.m_num_select_store_axiom;
         TRACE("array", tout << "select-stored " << new_prop << "\n";);
         return new_prop;
     }
diff --git a/src/sat/smt/array_solver.h b/src/sat/smt/array_solver.h
index f0ac956e8..c515b5886 100644
--- a/src/sat/smt/array_solver.h
+++ b/src/sat/smt/array_solver.h
@@ -90,19 +90,34 @@ namespace array {
                 is_default,
                 is_congruence
             };
+            enum class state_t {
+                is_new,
+                is_delayed,
+                is_applied
+            };
             kind_t      m_kind;
+            state_t     m_state { state_t::is_new };
             euf::enode* n;
             euf::enode* select;
-            bool        m_delayed { false };
             axiom_record(kind_t k, euf::enode* n, euf::enode* select = nullptr) : m_kind(k), n(n), select(select) {}
 
-            bool is_delayed() const { return m_delayed; }
+            bool is_delayed() const { return m_state == state_t::is_delayed; }
+            bool is_applied() const { return m_state == state_t::is_applied; }
+            void set_new() { m_state = state_t::is_new; }
+            void set_applied() { m_state = state_t::is_applied; }
+            void set_delayed() { m_state = state_t::is_delayed; }
 
             struct hash {
                 solver& s;
                 hash(solver& s) :s(s) {}
                 unsigned operator()(unsigned idx) const {
                     auto const& r = s.m_axiom_trail[idx];
+                    if (r.m_kind == kind_t::is_select) {
+                        unsigned h = mk_mix(r.n->get_expr_id(), (unsigned)r.m_kind, r.select->get_arg(1)->get_expr_id());
+                        for (unsigned i = 2; i < r.select->num_args(); ++i)
+                            h = mk_mix(h, 1, r.select->get_arg(i)->get_expr_id());
+                        return h;
+                    }
                     return mk_mix(r.n->get_expr_id(), (unsigned)r.m_kind, r.select ? r.select->get_expr_id() : 1);
                 }
             };
@@ -113,7 +128,14 @@ namespace array {
                 unsigned operator()(unsigned a, unsigned b) const {
                     auto const& p = s.m_axiom_trail[a];
                     auto const& r = s.m_axiom_trail[b];
-                    return p.n == r.n && p.select == r.select && p.m_kind == r.m_kind;
+                    if (p.m_kind != r.m_kind || p.n != r.n)
+                        return false;
+                    if (p.m_kind != kind_t::is_select)                        
+                        return p.select == r.select;
+                    for (unsigned i = p.select->num_args(); i-- > 1; )
+                        if (p.select->get_arg(i) != r.select->get_arg(i))
+                            return false;
+                    return true;
                 }
             };
         };
@@ -125,13 +147,16 @@ namespace array {
         unsigned              m_qhead { 0 };
         unsigned              m_delay_qhead { 0 };
         bool                  m_enable_delay { true };
-        struct set_delay_bit;
+        struct reset_new;
         void push_axiom(axiom_record const& r);
         bool propagate_axiom(unsigned idx);
         bool assert_axiom(unsigned idx);
         bool assert_select(unsigned idx, axiom_record & r);
         bool assert_default(axiom_record & r);
         bool is_relevant(axiom_record const& r) const;
+        void set_applied(unsigned idx) { m_axiom_trail[idx].set_applied(); }
+        bool is_applied(unsigned idx) const { return m_axiom_trail[idx].is_applied(); }
+        bool is_delayed(unsigned idx) const { return m_axiom_trail[idx].is_delayed(); }
 
         axiom_record select_axiom(euf::enode* s, euf::enode* n) { return axiom_record(axiom_record::kind_t::is_select, n, s); }
         axiom_record default_axiom(euf::enode* n) { return axiom_record(axiom_record::kind_t::is_default, n); }