diff --git a/src/nlsat/nlsat_solver.h b/src/nlsat/nlsat_solver.h
index 3668629cd..08902e709 100644
--- a/src/nlsat/nlsat_solver.h
+++ b/src/nlsat/nlsat_solver.h
@@ -21,10 +21,10 @@ Revision History:
 #ifndef NLSAT_SOLVER_H_
 #define NLSAT_SOLVER_H_
 
-#include"nlsat_types.h"
-#include"params.h"
-#include"statistics.h"
-#include"rlimit.h"
+#include"nlsat/nlsat_types.h"
+#include"util/params.h"
+#include"util/statistics.h"
+#include"util/rlimit.h"
 
 namespace nlsat {
 
diff --git a/src/nlsat/nlsat_types.h b/src/nlsat/nlsat_types.h
index 11e063a17..70da98e32 100644
--- a/src/nlsat/nlsat_types.h
+++ b/src/nlsat/nlsat_types.h
@@ -19,10 +19,10 @@ Revision History:
 #ifndef NLSAT_TYPES_H_
 #define NLSAT_TYPES_H_
 
-#include"polynomial.h"
-#include"buffer.h"
-#include"sat_types.h"
-#include"z3_exception.h"
+#include"math/polynomial/polynomial.h"
+#include"util/buffer.h"
+#include"sat/sat_types.h"
+#include"util/z3_exception.h"
 
 namespace algebraic_numbers {
     class anum;
diff --git a/src/util/lp/nra_solver.cpp b/src/util/lp/nra_solver.cpp
index 08b17030c..6ccc73633 100644
--- a/src/util/lp/nra_solver.cpp
+++ b/src/util/lp/nra_solver.cpp
@@ -5,18 +5,28 @@
 
 #pragma once
 #include "util/lp/nra_solver.h"
+#include "nlsat/nlsat_solver.h"
 
 namespace lp {
 
     struct nra_solver::imp {
         lean::lar_solver& s;
+        reslimit      m_limit;  // TBD: extract from lar_solver
+        params_ref    m_params; // TBD: pass from outside
 
-        svector<lean::var_index>         m_vars;
-        vector<svector<lean::var_index>> m_monomials;
+        struct mon_eq {
+            mon_eq(lean::var_index v, svector<lean::var_index> const& vs):
+                m_v(v), m_vs(vs) {}
+            lean::var_index          m_v;
+            svector<lean::var_index> m_vs;
+        };
+
+        vector<mon_eq>                   m_monomials;
         unsigned_vector                  m_lim;
+        mutable std::unordered_map<lean::var_index, rational> m_variable_values; // current model
 
-        imp(lean::lar_solver& s): s(s) {
-            m_lim.push_back(0);
+        imp(lean::lar_solver& s): 
+            s(s) {
         }
 
         lean::final_check_status check_feasible() {
@@ -24,21 +34,70 @@ namespace lp {
         }
 
         void add(lean::var_index v, unsigned sz, lean::var_index const* vs) {
-            m_vars.push_back(v);
-            m_monomials.push_back(svector<lean::var_index>(sz, vs));
+            m_monomials.push_back(mon_eq(v, svector<lean::var_index>(sz, vs)));
         }
 
         void push() {
-            m_lim.push_back(m_vars.size());
+            m_lim.push_back(m_monomials.size());
         }
 
         void pop(unsigned n) {
+            if (n == 0) return;
             SASSERT(n < m_lim.size());
+            m_monomials.shrink(m_lim[m_lim.size() - n]);
             m_lim.shrink(m_lim.size() - n);       
-            m_vars.shrink(m_lim.back());
-            m_monomials.shrink(m_lim.back());
         }
 
+        /*
+          \brief Check if polynomials are well defined.
+          multiply values for vs and check if they are equal to value for v.
+          epsilon has been computed.
+        */
+        bool check_assignment(mon_eq const& m) const {
+            rational r1 = m_variable_values[m.m_v];
+            rational r2(1);
+            for (auto w : m.m_vs) {
+                r2 *= m_variable_values[w];
+            }
+            return r1 == r2;
+        }
+
+        bool check_assignments() const {
+            s.get_model(m_variable_values);
+            for (auto const& m : m_monomials) {
+                if (!check_assignment(m)) return false;
+            }
+            return true;
+        }
+
+
+        /**
+           \brief one-shot nlsat check.
+           A one shot checker is the least functionality that can 
+           enable non-linear reasoning. 
+           In addition to checking satisfiability we would also need
+           to identify equalities in the model that should be assumed
+           with the remaining solver.
+
+           TBD: use partial model from lra_solver to prime the state of nlsat_solver.
+        */
+        lbool check_nlsat() {
+            nlsat::solver solver(m_limit, m_params);
+            // add linear inequalities from lra_solver
+            // add polynomial definitions.
+            for (auto const& m : m_monomials) {
+                add_monomial_eq(solver, m);
+            }
+            lbool r = solver.check();
+            if (r == l_true) {
+                // TBD extract model.
+            }
+            return r;
+        }                
+
+        void add_monomial_eq(nlsat::solver& solver, mon_eq const& m) {
+            
+        }
     };
 
     nra_solver::nra_solver(lean::lar_solver& s) {