diff --git a/src/math/polysat/saturation.cpp b/src/math/polysat/saturation.cpp
index 65c46d19a..c6405e0c5 100644
--- a/src/math/polysat/saturation.cpp
+++ b/src/math/polysat/saturation.cpp
@@ -1199,6 +1199,10 @@ namespace polysat {
      *   - then index on patterns or features of literals?
      */
     bool saturation::has_upper_bound(pvar x, conflict& core, rational& bound, signed_constraint& x_le_bound) {
+
+        bool found = s.m_viable.has_upper_bound(x, bound, x_le_bound);
+        verbose_stream() << "found " << found << "\n";
+        
         auto& m = s.var2pdd(x);        
         pdd y = s.var(x);
         for (auto const& c : core) {
@@ -1223,6 +1227,10 @@ namespace polysat {
     }
 
     bool saturation::has_lower_bound(pvar x, conflict& core, rational& bound, signed_constraint& x_ge_bound) {
+
+        bool found = s.m_viable.has_lower_bound(x, bound, x_ge_bound);
+        verbose_stream() << "found " << found << "\n";
+               
         auto& m = s.var2pdd(x);        
         pdd y = s.var(x);
         for (auto const& c : core) {
@@ -1314,10 +1322,9 @@ namespace polysat {
         pdd b = a, c = a, y = a;
         rational b_val, c_val, y_val, x_bound;
         signed_constraint x_ge_bound, x_le_bound, b_bound, ax_bound;
-        if (is_AxB_l_Y(x, a_l_b, a, b, y) && y.is_val() && s.try_eval(b, b_val) && !y.is_zero() && !a.is_val()) {
+        if (is_AxB_l_Y(x, a_l_b, a, b, y) && s.try_eval(y, y_val) && s.try_eval(b, b_val) && !y_val.is_zero() && !a.is_val()) {
             verbose_stream() << a_l_b << "   a " << a << "   b " << b << " := " << dd::val_pp(m, b_val, false) << "   y " << y << "\n";
             SASSERT(!a.is_zero());
-            y_val = y.val();
 
             // define c := -b
             c = -b;
diff --git a/src/math/polysat/viable.cpp b/src/math/polysat/viable.cpp
index ebfcb81fb..66a0ac40c 100644
--- a/src/math/polysat/viable.cpp
+++ b/src/math/polysat/viable.cpp
@@ -643,6 +643,43 @@ namespace polysat {
         return query<query_t::max_viable>(v, hi);
     }
 
+    bool viable::has_upper_bound(pvar v, rational& out_hi, signed_constraint& out_c) {
+        entry const* first = m_units[v];
+        entry const* e = first;
+        do {
+            if (!e->refined) {
+                verbose_stream() << "has-upper-bound " << e->src << " " << e->interval << "\n";
+                auto const& lo = e->interval.lo();
+                auto const& hi = e->interval.hi();
+                if (lo.is_val() && hi.is_val() && lo.val() > hi.val()) {
+                    out_c = e->src;
+                    out_hi = lo.val() - 1;
+                    return true;
+                }
+            }
+            e = e->next();
+        }
+        while (e != first);
+
+        return false;
+    }
+
+    bool viable::has_lower_bound(pvar v, rational& out_hi, signed_constraint& out_c) {
+        entry const* first = m_units[v];
+        entry const* e = first;
+        do {
+            if (!e->refined) {
+                verbose_stream() << "has-upper-bound " << e->src << " " << e->interval << "\n";                
+            }
+            e = e->next();
+        }
+        while (e != first);
+
+        return false;
+
+        return false;
+    }
+
     template <query_t mode>
     lbool viable::query(pvar v, typename query_result<mode>::result_t& result) {
         // max number of interval refinements before falling back to the univariate solver
diff --git a/src/math/polysat/viable.h b/src/math/polysat/viable.h
index ce76eae97..cb1feb822 100644
--- a/src/math/polysat/viable.h
+++ b/src/math/polysat/viable.h
@@ -184,6 +184,19 @@ namespace polysat {
          */
         lbool max_viable(pvar v, rational& out_hi);
 
+
+        /**
+         * Query for an upper bound literal for v together with justification.
+         * @return true if a non-trivial upper bound is found, return justifying constraint.
+         */
+        bool has_upper_bound(pvar v, rational& out_hi, signed_constraint& out_c);
+
+        /**
+         * Query for an lower bound literal for v together with justification.
+         * @return true if a non-trivial lower bound is found, return justifying constraint.
+         */
+        bool has_lower_bound(pvar v, rational& out_hi, signed_constraint& out_c);
+
         /**
          * Find a next viable value for variable.
          */