arith-theory-axiom reducer to handle arithmetic axioms

src/muz/spacer/spacer_proof_utils.h

@@ -22,6 +22,7 @@ Revision History:
 
 namespace spacer {
     
+    bool is_arith_lemma(ast_manager& m, proof* pr);
     bool is_farkas_lemma(ast_manager& m, proof* pr);
 /*
  * iterator, which traverses the proof in depth-first post-order.
@@ -46,8 +47,71 @@ private:
     class iuc_proof;
     void pp_proof_dot(ast_manager& m, proof* pr, iuc_proof* iuc_pr = nullptr);
     
+    class theory_axiom_reducer
+    {
+    public:
+        theory_axiom_reducer(ast_manager& m) : m(m), m_pinned(m) {}
 
+        // reduce theory axioms and return transformed proof
+        proof_ref reduce(proof* pr);
+        
+    private:
+        ast_manager &m;
+        
+        // tracking all created expressions
+        expr_ref_vector m_pinned;
+        
+        // maps each proof of a clause to the transformed subproof of that clause
+        obj_map<proof, proof*> m_cache;
+        
+        void reset();
+    };
 
-void reduce_hypotheses(proof_ref &pr);
+    class hypothesis_reducer
+    {
+    public:
+        hypothesis_reducer(ast_manager &m) : m(m), m_pinned(m) {}
+        
+        // reduce hypothesis and return transformed proof
+        proof_ref reduce(proof* pf);
+
+    private:
+        typedef obj_hashtable<expr> expr_set;
+        
+        ast_manager &m;
+        // tracking all created expressions
+        expr_ref_vector m_pinned;
+        
+        // maps each proof of a clause to the transformed subproof of that clause
+        obj_map<proof, proof*> m_cache;
+        
+        // maps each unit literals to the transformed subproof of that unit
+        obj_map<expr, proof*> m_units;
+        
+        // -- all hypotheses in the the proof
+        obj_hashtable<expr> m_hyps;
+        
+        // marks hypothetical proofs
+        ast_mark m_hypmark;
+        
+        std::vector<expr_set> m_pinned_hyp_sets; // tracking all created sets of hypothesis
+        obj_map<expr, expr_set*> m_hyp_anchestor; // maps each proof to the set of hypothesis it contains, needed to avoid creating cycles in the proof.
+        
+        // stack
+        ptr_vector<proof> m_todo;
+        
+        void reset();
+        proof* compute_transformed_proof(proof* pf);
+
+        void compute_hypmarks_and_hyps(proof* pr);
+        bool compute_hypmark_from_parents(proof *pr);
+        void collect_units(proof* pr);
+        
+        // returns true if (hypothesis (not a)) would be reduced
+        bool is_reduced(expr *a);
+        
+        proof* mk_lemma_core(proof *pf, expr *fact);
+        proof* mk_unit_resolution_core(unsigned num_args, proof* const *args);
+    };
 }
 #endif