add outline for ule constraints, change bit to var constraints

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/math/polysat/ule_constraint.h

@@ -0,0 +1,43 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    polysat constraints
+
+Abstract:
+
+    Polynomial equality constriants
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+
+--*/
+#pragma once
+#include "math/polysat/constraint.h"
+
+
+namespace polysat {
+
+    class ule_constraint : public constraint {
+        pdd m_lhs;
+        pdd m_rhs;
+    public:
+        ule_constraint(unsigned lvl, pdd const& l, pdd const& r, p_dependency_ref& dep):
+            constraint(lvl, dep, ckind_t::ule_t), m_lhs(l), m_rhs(r) {
+            m_vars.append(l.free_vars());
+            for (auto v : r.free_vars())
+                if (!m_vars.contains(v))
+                    m_vars.push_back(v);
+        }
+        ~ule_constraint() override {}
+        std::ostream& display(std::ostream& out) const override;
+        bool propagate(solver& s, pvar v) override;
+        constraint* resolve(solver& s, pvar v) override;
+        bool is_always_false() override;
+        bool is_currently_false(solver& s) override;
+        void narrow(solver& s) override;
+    };
+
+}