diff --git a/src/math/polysat/fixplex.h b/src/math/polysat/fixplex.h
index f6af50ccd..8cbf49956 100644
--- a/src/math/polysat/fixplex.h
+++ b/src/math/polysat/fixplex.h
@@ -252,12 +252,12 @@ namespace polysat {
         void fixed_var_eh(row const& r, var_t x);
         void eq_eh(var_t x, var_t y, row const& r1, row const& r2);
         lbool propagate_bounds(row const& r);
-        lbool propagate_bounds(ineq const& i);
-        lbool new_bound(row const& r, var_t x, mod_interval<numeral> const& range);
-        lbool new_bound(ineq const& i, var_t x, numeral const& lo, numeral const& hi, u_dependency* a = nullptr, u_dependency* b = nullptr);
-        lbool conflict(ineq const& i, u_dependency* a = nullptr, u_dependency* b = nullptr);
-        lbool conflict(u_dependency* a);
-        lbool conflict(u_dependency* a, u_dependency* b) { return conflict(m_deps.mk_join(a, b)); }
+        bool propagate_bounds(ineq const& i);
+        bool new_bound(row const& r, var_t x, mod_interval<numeral> const& range);
+        bool new_bound(ineq const& i, var_t x, numeral const& lo, numeral const& hi, u_dependency* a = nullptr, u_dependency* b = nullptr, u_dependency* c = nullptr, u_dependency* d = nullptr);
+        void conflict(ineq const& i, u_dependency* a = nullptr, u_dependency* b = nullptr, u_dependency* c = nullptr, u_dependency* d = nullptr);
+        void conflict(u_dependency* a);
+        void conflict(u_dependency* a, u_dependency* b, u_dependency* c = nullptr, u_dependency* d = nullptr) { conflict(m_deps.mk_join(m_deps.mk_join(a, b), m_deps.mk_join(c, d))); }
         u_dependency* row2dep(row const& r);
         void pivot(var_t x_i, var_t x_j, numeral const& b, numeral const& value);
         numeral value2delta(var_t v, numeral const& new_value) const;
@@ -297,7 +297,9 @@ namespace polysat {
         // facilities for handling inequalities
         void add_ineq(var_t v, var_t w, unsigned dep, bool strict);
         void touch_var(var_t x);
-        lbool check_ineqs();
+        bool ineqs_are_violated();
+        bool ineqs_are_satisfied();
+        void reset_ineqs_to_check();
 
         bool is_solved(row const& r) const;
         bool is_solved(var_t v) const { SASSERT(is_base(v)); return is_solved(base2row(v)); }
diff --git a/src/math/polysat/fixplex_def.h b/src/math/polysat/fixplex_def.h
index 722621189..3c61494ec 100644
--- a/src/math/polysat/fixplex_def.h
+++ b/src/math/polysat/fixplex_def.h
@@ -149,13 +149,17 @@ namespace polysat {
                 return l_false;
             case l_undef:
                 m_to_patch.insert(v);
-                if (l_false == check_ineqs())
+                if (ineqs_are_violated())
                     return l_false;
                 return l_undef;
             }
         }
         SASSERT(well_formed());
-        return check_ineqs();
+        if (ineqs_are_violated())
+            return l_false;
+        if (ineqs_are_satisfied())
+            return l_true;
+        return l_undef;
     }
 
     template<typename Ext>
@@ -352,7 +356,6 @@ namespace polysat {
                 return l_undef;
         }
 
-
         pivot(x, y, b, new_value);
 
         return l_true;
@@ -499,8 +502,7 @@ namespace polysat {
     }
 
     template<typename Ext>
-    typename fixplex<Ext>::numeral
-        fixplex<Ext>::value2error(var_t v, numeral const& value) const {
+    typename fixplex<Ext>::numeral fixplex<Ext>::value2error(var_t v, numeral const& value) const {
         if (in_bounds(v))
             return 0;
         SASSERT(lo(v) != hi(v));
@@ -519,6 +521,7 @@ namespace polysat {
      */
     template<typename Ext>
     void fixplex<Ext>::set_bounds(var_t v, numeral const& l, numeral const& h, unsigned dep) {
+        ensure_var(v);
         update_bounds(v, l, h, mk_leaf(dep));
         if (in_bounds(v))
             return;
@@ -571,6 +574,8 @@ namespace polysat {
 
     template<typename Ext>
     void fixplex<Ext>::add_ineq(var_t v, var_t w, unsigned dep, bool strict) {
+        ensure_var(v);
+        ensure_var(w);
         unsigned idx = m_ineqs.size();        
         m_var2ineqs.reserve(std::max(v, w) + 1);
         m_var2ineqs[v].push_back(idx);
@@ -604,31 +609,51 @@ namespace polysat {
     }
 
     template<typename Ext>
-    lbool fixplex<Ext>::check_ineqs() {
-        m_vars_to_untouch.reset();
+    void fixplex<Ext>::reset_ineqs_to_check() {
+        for (auto idx : m_ineqs_to_check) {
+            if (idx >= m_ineqs.size())
+                continue;
+            auto& ineq = m_ineqs[idx];
+             m_var_is_touched.setx(ineq.v, false, false);
+             m_var_is_touched.setx(ineq.w, false, false);
+             ineq.is_active = false;
+        }
+        m_ineqs_to_check.reset();
+    }
+
+    /**
+    * Check if the current assignment satisfies the inequalities
+    */
+    template<typename Ext>
+    bool fixplex<Ext>::ineqs_are_satisfied() {
         for (auto idx : m_ineqs_to_check) {
             if (idx >= m_ineqs.size())
                 continue;
             auto& ineq = m_ineqs[idx];
             var_t v = ineq.v;
             var_t w = ineq.w;
-            if (ineq.strict && value(v) >= value(w)) {
-                IF_VERBOSE(0, verbose_stream() << "violated v" << v << " < v" << w << "\n");
-                return l_false;
-            }
-            if (!ineq.strict && value(v) > value(w)) {
-                IF_VERBOSE(0, verbose_stream() << "violated v" << v << " <= v" << w << "\n");
-                return l_false;
-            }
-            ineq.is_active = false;
-            m_vars_to_untouch.push_back(v);
-            m_vars_to_untouch.push_back(w);
+            if (ineq.strict && value(v) >= value(w)) 
+                return false;            
+            if (!ineq.strict && value(v) > value(w))
+                return false;            
         }
-        for (auto v : m_vars_to_untouch)
-            m_var_is_touched.set(v, false);
-        m_ineqs_to_check.reset();
-        m_vars_to_untouch.reset();
-        return l_true;
+        reset_ineqs_to_check();
+        return true;
+    }
+
+    /**
+    * Propagate bounds and check if the current inequalities are satisfied
+    */
+    template<typename Ext>
+    bool fixplex<Ext>::ineqs_are_violated() {
+        for (unsigned i = 0; i < m_ineqs_to_check.size(); ++i) {
+            unsigned idx = m_ineqs_to_check[i];
+            if (idx >= m_ineqs.size())
+                continue;
+            if (!propagate_bounds(m_ineqs[idx]))
+                return true;
+        }
+        return false;
     }
 
 
@@ -1087,16 +1112,16 @@ namespace polysat {
         m_var_eqs.push_back(var_eq(x, y, r1, r2));
     }    
 
-
     template<typename Ext>
     lbool fixplex<Ext>::propagate_bounds() {
         lbool r = l_true;
         for (unsigned i = 0; r == l_true && i < m_rows.size(); ++i) 
             r = propagate_bounds(row(i));
+        if (r != l_true)
+            return r;
         for (auto ineq : m_ineqs) {
-            if (r != l_true)
-                break;
-            r = propagate_bounds(ineq);
+            if (!propagate_bounds(ineq))
+                return l_false;
         }
         return r;
     }
@@ -1132,7 +1157,7 @@ namespace polysat {
 
         if (free_v != null_var) {
             range = (-range) * free_c;
-            lbool res = new_bound(r, free_v, range);
+            lbool res = new_bound(r, free_v, range) ? l_true : l_false;
             SASSERT(in_bounds(free_v));
             return res;
         }
@@ -1140,7 +1165,7 @@ namespace polysat {
             var_t v = e.var();
             SASSERT(!is_free(v));
             auto range1 = range - m_vars[v] * e.coeff();
-            lbool res = new_bound(r, v, range1);
+            lbool res = new_bound(r, v, range1) ? l_true : l_false;
             if (res != l_true)
                 return res;
             // SASSERT(in_bounds(v));
@@ -1149,56 +1174,61 @@ namespace polysat {
     }
 
     template<typename Ext>
-    lbool fixplex<Ext>::propagate_bounds(ineq const& i) {
+    bool fixplex<Ext>::propagate_bounds(ineq const& i) {
         // v < w  & lo(v) + 1 = 0  -> conflict
-        // v < w  & hi(w) = 0      -> conflict
-        // v < w  & lo(v) >= hi(w) -> conflict
-        // v <= w & lo(v) >  hi(w) -> conflict
-        // v < w  & hi(v) >= hi(w) -> hi(v) := hi(w) - 1
-        // v < w  & lo(v) >= lo(w) -> lo(w) := lo(v) + 1
+        // v < w  & lo(w) = 0 & hi(w) = 1 -> conflict
+        // v < w  & hi(w) != 0 & lo(w) <= hi(w) & hi(w) - 1 <= lo(v) -> conflict
+        // v <= w & hi(w) != 0 & lo(w) <= hi(w) & hi(w) <= lo(v) -> conflict
+        // v < w  & hi(w) != 0 & lo(w) <= hi(w) <= hi(v) -> hi(v) := hi(w) - 1
+        // v < w  & lo(w) <= lo(v) -> lo(w) := lo(v) + 1
         // v <= w & hi(v) >  hi(w) -> hi(v) := hi(w)
         // v <= w & lo(v) >  lo(w) -> lo(w) := lo(w)
         var_t v = i.v, w = i.w;
         bool s = i.strict;
-        if (s && lo(v) + 1 == 0)
-            return conflict(i, m_vars[v].m_lo_dep);
-        else if (s && hi(w) == 0)
-            return conflict(i, m_vars[v].m_hi_dep);
-        else if (s && lo(v) >= hi(w))
-            return conflict(i, m_vars[v].m_lo_dep, m_vars[w].m_hi_dep);
-        else if (!s && lo(v) > hi(w))
-            return conflict(i, m_vars[v].m_lo_dep, m_vars[w].m_hi_dep);
-        else if (s && hi(v) >= hi(w)) {
-            SASSERT(lo(v) < hi(w));
-            SASSERT(hi(w) != 0);
-            return new_bound(i, v, lo(v), hi(w) - 1, m_vars[v].m_hi_dep, m_vars[w].m_hi_dep);
-        }
-        else if (s && lo(v) >= lo(w)) {
-            SASSERT(lo(v) + 1 != 0);
-            SASSERT(hi(w) > lo(v));
-            return new_bound(i, w, lo(v) + 1, hi(w), m_vars[v].m_lo_dep, m_vars[w].m_lo_dep);
-        }
-        else if (!s && hi(v) > hi(w)) {
-            SASSERT(lo(v) <= hi(w));
-            return new_bound(i, v, lo(v), hi(w), m_vars[v].m_hi_dep, m_vars[w].m_hi_dep);
-        }
-        else if (!s && lo(v) > lo(w)) {
-            SASSERT(lo(v) <= hi(w));
-            return new_bound(i, w, lo(v), hi(w), m_vars[v].m_lo_dep, m_vars[w].m_lo_dep);
-        }
-        return l_true;
+        auto* vlo = m_vars[v].m_lo_dep, *vhi = m_vars[v].m_hi_dep;
+        auto* wlo = m_vars[w].m_lo_dep, *whi = m_vars[w].m_hi_dep;
+        if (s && lo(v) + 1 == 0 && is_fixed(v))
+            return conflict(i, vlo, vhi), false;
+        if (s && lo(w) == 0 && is_fixed(w))
+            return conflict(i, wlo, whi), false;
+        if (s && hi(w) != 0 && lo(w) <= hi(w) && lo(v) <= hi(v) && hi(w) - 1 <= lo(v))
+            return conflict(i, vlo, wlo, whi), false;
+        if (s && hi(v) == 0 && lo(w) < hi(w) && hi(w) - 1 <= lo(v))
+            return conflict(i, vlo, vhi, wlo, whi), false;
+        if (!s && hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= lo(v) && lo(v) <= hi(v))
+            return conflict(i, vlo, vhi, wlo, whi), false;
+        if (!s && hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= lo(v) && hi(v) == 0)
+            return conflict(i, vlo, vhi, wlo, whi), false;
+        if (s && hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= hi(v) && !new_bound(i, v, lo(v), hi(w) - 1, wlo, vhi, whi))
+            return false;             
+        if (s && lo(w) <= lo(v) && !new_bound(i, w, lo(v) + 1, hi(w), vlo, wlo))
+            return false;
+        if (s && hi(w) != 0 && hi(w) - 1 <= lo(v) && lo(v) <= hi(v) && hi(w) < lo(w) && !new_bound(i, w, lo(w), 0, wlo, whi, vlo, vhi))
+            return false;
+        if (s && hi(w) == 1 && !is_fixed(w) && !new_bound(i, w, lo(w), 0, wlo, whi))
+            return false;
+        if (!s && hi(v) > hi(w) && !new_bound(i, v, lo(v), hi(w), vhi, whi))
+            return false;
+        if (!s && lo(v) > lo(w) && !new_bound(i, w, lo(v), hi(w), vlo, wlo))
+            return false;     
+        if (!s && hi(w) != 0 && hi(w) < lo(w) && hi(w) <= lo(v) && lo(v) <= hi(v) && !new_bound(i, w, lo(w), 0, vlo, vhi, wlo, whi))
+            return false;
+        if (hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= lo(v) && !new_bound(i, v, 0, hi(v), wlo, vlo, whi))
+            return false;
+
+        return true;
     }
 
     template<typename Ext>
-    lbool fixplex<Ext>::conflict(ineq const& i, u_dependency* a, u_dependency* b) {
-        return conflict(a, m_deps.mk_join(mk_leaf(i.dep), b));
+    void fixplex<Ext>::conflict(ineq const& i, u_dependency* a, u_dependency* b, u_dependency* c, u_dependency* d) {
+        conflict(a, m_deps.mk_join(mk_leaf(i.dep), m_deps.mk_join(b, m_deps.mk_join(c, d))));
     }
 
     template<typename Ext>
-    lbool fixplex<Ext>::conflict(u_dependency* a) {
+    void fixplex<Ext>::conflict(u_dependency* a) {
         m_unsat_core.reset();
         m_deps.linearize(a, m_unsat_core);
-        return l_false;
+        TRACE("polysat", tout << "core: " << m_unsat_core << "\n";);
     }
 
     template<typename Ext>
@@ -1213,31 +1243,31 @@ namespace polysat {
     }
 
     template<typename Ext>
-    lbool fixplex<Ext>::new_bound(ineq const& i, var_t x, numeral const& l, numeral const& h, u_dependency* a, u_dependency* b) {
+    bool fixplex<Ext>::new_bound(ineq const& i, var_t x, numeral const& l, numeral const& h, u_dependency* a, u_dependency* b, u_dependency* c, u_dependency* d) {
         bool was_fixed = lo(x) + 1 == hi(x);
-        u_dependency* dep = m_deps.mk_join(mk_leaf(i.dep), m_deps.mk_join(a, b));
+        u_dependency* dep = m_deps.mk_join(mk_leaf(i.dep), m_deps.mk_join(a, m_deps.mk_join(b, m_deps.mk_join(c, d))));
         update_bounds(x, l, h, dep);
         if (m_vars[x].is_empty())
-            return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep);
+            return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep), false;
         else if (!was_fixed && lo(x) + 1 == hi(x)) {
             // TBD: track based on inequality not row
             // fixed_var_eh(r, x);
         }
-        return l_true;
+        return true;
     }
 
     template<typename Ext>
-    lbool fixplex<Ext>::new_bound(row const& r, var_t x, mod_interval<numeral> const& range) {
+    bool fixplex<Ext>::new_bound(row const& r, var_t x, mod_interval<numeral> const& range) {
         if (range.is_free())
             return l_true;
         bool was_fixed = lo(x) + 1 == hi(x);
         update_bounds(x, range.lo, range.hi, row2dep(r));
         IF_VERBOSE(0, verbose_stream() << "new-bound v" << x << " " << m_vars[x] << "\n");
-        if (m_vars[x].is_empty()) 
-            return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep);
+        if (m_vars[x].is_empty())
+            return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep), false;
         else if (!was_fixed && lo(x) + 1 == hi(x)) 
             fixed_var_eh(r, x);
-        return l_true;
+        return true;
     }
 
     template<typename Ext>    
@@ -1249,6 +1279,12 @@ namespace polysat {
             if (vi.m_is_base) out << "b:" << vi.m_base2row << " " << pp(m_rows[vi.m_base2row].m_value) << " ";
             out << "\n";
         }
+        for (auto const& i : m_ineqs) {
+            if (i.strict)
+                out << "v" << i.v << " < v" << i.w << "\n";
+            else
+                out << "v" << i.v << " <= v" << i.w << "\n";
+        }
         return out;
     }
 
diff --git a/src/math/polysat/linear_solver.cpp b/src/math/polysat/linear_solver.cpp
index 535d9c670..e2e127442 100644
--- a/src/math/polysat/linear_solver.cpp
+++ b/src/math/polysat/linear_solver.cpp
@@ -286,12 +286,10 @@ namespace polysat {
     lbool linear_solver::check() { 
         lbool res = l_true;
         m_unsat_f = nullptr;
-        for (auto* f : m_fix) {
-            if (!f)
-                continue;
-            lbool r = f->make_feasible();
+        for (auto* fp : m_fix_ptr) {
+            lbool r = fp->make_feasible();
             if (r == l_false) {
-                m_unsat_f = f;
+                m_unsat_f = fp;
                 return r;
             }
             if (r == l_undef)
@@ -313,12 +311,13 @@ namespace polysat {
     }
 
     // current value assigned to (linear) variable according to tableau.
-    rational linear_solver::value(pvar v) { 
+    bool linear_solver::value(pvar v, rational& val) { 
         unsigned sz = s.size(v);
         auto* fp = sz2fixplex(sz);
         if (!fp)
-            return rational::zero();
-        return fp->get_value(pvar2var(sz, v));
+            return false;
+        val = fp->get_value(pvar2var(sz, v));
+        return true;
     }
     
 };
diff --git a/src/math/polysat/linear_solver.h b/src/math/polysat/linear_solver.h
index 88602a4e3..4ec9d855c 100644
--- a/src/math/polysat/linear_solver.h
+++ b/src/math/polysat/linear_solver.h
@@ -41,8 +41,6 @@ namespace polysat {
             inc_level_i,
             add_var_i,
             add_mono_i,
-            add_ineq_i,
-            add_row_i,
             set_active_i
         };
 
@@ -135,7 +133,7 @@ namespace polysat {
         void unsat_core(ptr_vector<constraint>& constraints, unsigned_vector& deps);
 
         // current value assigned to (linear) variable according to tableau.
-        rational value(pvar v);
+        bool value(pvar v, rational& val);
 
         std::ostream& display(std::ostream& out) const { return out; }
         void collect_statistics(::statistics & st) const {}
diff --git a/src/test/fixplex.cpp b/src/test/fixplex.cpp
index d1d35670c..c24e1851d 100644
--- a/src/test/fixplex.cpp
+++ b/src/test/fixplex.cpp
@@ -1,5 +1,10 @@
 #include "math/polysat/fixplex.h"
 #include "math/polysat/fixplex_def.h"
+#include "ast/bv_decl_plugin.h"
+#include "ast/reg_decl_plugins.h"
+#include "smt/smt_kernel.h"
+#include "smt/params/smt_params.h"
+
 
 namespace polysat {
 
@@ -118,7 +123,6 @@ namespace polysat {
     static void test_gcd() {
         std::cout << "gcd\n";
         uint64_ext::manager e;
-        uint64_t x = 0, y = 0, z = 0, a = 0, b = 0;
         uint64_t g = e.gcd(15, 27);
         std::cout << g << "\n";
         std::cout << 15 << " " << e.mul_inverse(15) << " " << 15*e.mul_inverse(15) << "\n";
@@ -126,9 +130,172 @@ namespace polysat {
         std::cout << 60 << " " << e.mul_inverse(60) << " " << 60*e.mul_inverse(60) << "\n";
         std::cout << 29 << " " << e.mul_inverse(29) << " " << 29*e.mul_inverse(29) << "\n";
     }
+
+    static void test_ineq1() {
+        std::cout << "ineq1\n";
+        scoped_fp fp;
+        var_t x = 0, y = 1;
+        fp.add_lt(x, y, 1);
+        fp.add_le(y, x, 2);
+        fp.run();
+    }
+
+    static void test_ineqs() {
+        var_t x = 0, y = 1;
+        unsigned nb = 6;
+        uint64_t bounds[6] = { 0, 1, 2, 10 , (uint64_t)-2, (uint64_t)-1 };
+        ast_manager m;
+        reg_decl_plugins(m);
+        bv_util bv(m);
+        expr_ref X(m.mk_const("x", bv.mk_sort(64)), m);
+        expr_ref Y(m.mk_const("y", bv.mk_sort(64)), m);
+        smt_params pa;
+        smt::kernel solver(m, pa);
+
+        auto mk_ult = [&](expr* a, expr* b) {
+            return m.mk_not(bv.mk_ule(b, a));
+        };
+
+        auto add_bound = [&](expr* x, uint64_t i, uint64_t j) {
+            expr_ref I(bv.mk_numeral(i, 64), m);
+            expr_ref J(bv.mk_numeral(j, 64), m);
+            if (i < j) {
+                solver.assert_expr(bv.mk_ule(I, x));
+                solver.assert_expr(mk_ult(x, J));
+            }
+            else if (i > j && j != 0)
+                solver.assert_expr(m.mk_or(bv.mk_ule(I, x), mk_ult(x, J)));
+            else if (i > j && j == 0)
+                solver.assert_expr(bv.mk_ule(I, x));
+        };
+
+        auto test_le = [&](bool test_le, uint64_t i, uint64_t j, uint64_t k, uint64_t l) {
+            if (i == j && i != 0)
+                return;
+            if (k == l && k != 0)
+                return;
+            scoped_fp fp;
+            fp.set_bounds(x, i, j, 1);
+            fp.set_bounds(y, k, l, 2);       
+            if (test_le)
+                fp.add_le(x, y, 3);
+            else
+                fp.add_lt(x, y, 3);
+
+            lbool feas = fp.make_feasible();
+
+            // validate result
+
+
+            solver.push();
+            if (test_le)
+                solver.assert_expr(bv.mk_ule(X, Y));
+            else 
+                solver.assert_expr(mk_ult(X, Y));
+            add_bound(X, i, j);
+            add_bound(Y, k, l);
+
+            lbool feas2 = solver.check();
+
+
+            if (feas == feas2) {
+                solver.pop(1);
+                return;
+            }
+
+
+            if (feas2 == l_false && feas == l_true) {
+                std::cout << "BUG!\n";
+                solver.pop(1);
+                return;
+            }
+
+            bool bad = false;
+
+            switch (feas) {
+            case l_false:     
+                for (unsigned c : fp.get_unsat_core())
+                    std::cout << c << "\n";
+                std::cout << "\n";
+                break;            
+            case l_true:
+            case l_undef:
+
+                // Check for missed bounds:
+                solver.push();
+                solver.assert_expr(m.mk_eq(X, bv.mk_numeral(fp.lo(x), 64)));
+                if (l_true != solver.check()) {
+                    std::cout << "missed lower bound on x\n";
+                    bad = true;
+                }
+                solver.pop(1);
+
+                solver.push();
+                solver.assert_expr(m.mk_eq(Y, bv.mk_numeral(fp.lo(y), 64)));
+                if (l_true != solver.check()) {
+                    std::cout << "missed lower bound on y\n";
+                    bad = true;
+                }
+                solver.pop(1);
+
+                if (fp.lo(x) != fp.hi(x) && fp.hi(x) != 0) {
+                    solver.push();
+                    solver.assert_expr(m.mk_eq(X, bv.mk_numeral(fp.hi(x)-1, 64)));
+                    if (l_true != solver.check()) {
+                        std::cout << "missed upper bound on x\n";
+                        bad = true;
+                    }
+                    solver.pop(1);
+                }
+
+                if (fp.lo(y) != fp.hi(y) && fp.hi(y) != 0) {
+                    solver.push();
+                    solver.assert_expr(m.mk_eq(Y, bv.mk_numeral(fp.hi(y) - 1, 64)));
+                    if (l_true != solver.check()) {
+                        std::cout << "missed upper bound on y\n";
+                        bad = true;
+                    }
+                    solver.pop(1);
+                }
+
+                if (bad) {
+                    std::cout << fp << "\n";
+                    std::cout << feas << " " << feas2 << "\n";
+                }
+
+                break;
+            }
+
+            // check assignment is valid when returning satisfiable.
+            if (false && feas == l_true) {
+                rational vx = fp.get_value(x);
+                rational vy = fp.get_value(y);
+                SASSERT(vx <= vy);
+                SASSERT(i >= j || (rational(i, rational::ui64()) <= vx && vx < rational(j, rational::ui64())));
+                SASSERT(k >= l || (rational(k, rational::ui64()) <= vy && vy < rational(l, rational::ui64())));
+
+            }
+
+            solver.pop(1);
+
+            return;            
+        };
+        for (unsigned i = 0; i < nb; ++i)
+            for (unsigned j = 0; j < nb; ++j)
+                for (unsigned k = 0; k < nb; ++k)
+                    for (unsigned l = 0; l < nb; ++l) {
+                        test_le(true, bounds[i], bounds[j], bounds[k], bounds[l]);
+                        test_le(false, bounds[i], bounds[j], bounds[k], bounds[l]);
+                    }
+    }
 }
 
 void tst_fixplex() {
+
+    polysat::test_ineq1();
+    polysat::test_ineqs();
+    return;
+
     polysat::test1();
     polysat::test2();
     polysat::test3();