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/****************************************************************************** |
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* Top contributors (to current version): |
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* Andrew Reynolds |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* Methods for counterexample-guided quantifier instantiation |
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* based on nested quantifier elimination. |
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*/ |
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#include "cvc5_private.h" |
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#ifndef CVC5__THEORY__QUANTIFIERS__CEQGI__NESTED_QE_H |
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#define CVC5__THEORY__QUANTIFIERS__CEQGI__NESTED_QE_H |
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#include <unordered_set> |
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#include "context/cdhashmap.h" |
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#include "expr/node.h" |
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namespace cvc5 { |
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class Env; |
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namespace theory { |
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namespace quantifiers { |
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class NestedQe |
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{ |
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using NodeNodeMap = context::CDHashMap<Node, Node>; |
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public: |
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NestedQe(Env& env); |
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~NestedQe() {} |
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/** |
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* Process quantified formula. If this returns true, then q was processed |
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* via nested quantifier elimination (either during this call or previously |
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* in this user context). If q was processed in this call, the lemma: |
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* (= q qqe) |
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* is added to lem, where qqe is the result of nested quantifier elimination |
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* on q. |
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*/ |
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bool process(Node q, std::vector<Node>& lems); |
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/** |
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* Have we processed q using the above method? |
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*/ |
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bool hasProcessed(Node q) const; |
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/** |
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* Get nested quantification. Returns true if q has nested quantifiers. |
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* Adds each nested quantifier in the body of q to nqs. |
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*/ |
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static bool getNestedQuantification(Node q, std::unordered_set<Node>& nqs); |
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/** |
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* Does quantified formula q have nested quantification? |
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*/ |
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static bool hasNestedQuantification(Node q); |
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/** |
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* Do nested quantifier elimination. Returns a formula that is equivalent to |
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* q and has no nested quantification. If keepTopLevel is false, then the |
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* returned formula is quantifier-free. Otherwise, it is a quantified formula |
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* with no nested quantification. |
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*/ |
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static Node doNestedQe(Env& env, Node q, bool keepTopLevel = false); |
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/** |
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* Run quantifier elimination on quantified formula q, where q has no nested |
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* quantification. This method invokes a subsolver for performing quantifier |
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* elimination. |
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*/ |
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static Node doQe(Env& env, Node q); |
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private: |
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/** Reference to the env */ |
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Env& d_env; |
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/** |
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* Mapping from quantified formulas q to the result of doNestedQe(q, true). |
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*/ |
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NodeNodeMap d_qnqe; |
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}; |
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} // namespace quantifiers |
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} // namespace theory |
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} // namespace cvc5 |
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#endif |