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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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* Preprocessor for the theory of quantifiers. |
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*/ |
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#include "cvc5_private.h" |
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#ifndef CVC5__THEORY__QUANTIFIERS__QUANTIFIERS_PREPROCESS_H |
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#define CVC5__THEORY__QUANTIFIERS__QUANTIFIERS_PREPROCESS_H |
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#include "proof/trust_node.h" |
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#include "smt/env_obj.h" |
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namespace cvc5 { |
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namespace theory { |
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namespace quantifiers { |
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/** |
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* Module for doing preprocessing that is pertinent to quantifiers. These |
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* operations cannot be done in the rewriter since e.g. preskolemization |
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* depends on knowing the polarity of the position in which quantifiers occur. |
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*/ |
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class QuantifiersPreprocess : protected EnvObj |
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{ |
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public: |
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QuantifiersPreprocess(Env& env); |
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/** preprocess |
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* |
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* This returns the result of applying simple quantifiers-specific |
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* pre-processing to n, including but not limited to: |
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* - pre-skolemization, |
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* - aggressive prenexing. |
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* The argument isInst is set to true if n is an instance of a previously |
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* registered quantified formula. If this flag is true, we do not apply |
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* certain steps like pre-skolemization since we know they will have no |
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* effect. |
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* |
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* The result is wrapped in a trust node of kind TrustNodeKind::REWRITE. |
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*/ |
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TrustNode preprocess(Node n, bool isInst = false) const; |
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private: |
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using NodePolPairHashFunction = PairHashFunction<Node, bool, std::hash<Node>>; |
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/** |
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* Pre-skolemize quantifiers. Return the pre-skolemized form of n. |
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* |
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* @param n The formula to preskolemize. |
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* @param polarity The polarity of n in the input. |
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* @param fvs The free variables |
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* @param visited Cache of visited (node, polarity) pairs. |
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*/ |
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Node preSkolemizeQuantifiers( |
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Node n, |
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bool polarity, |
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std::vector<TNode>& fvs, |
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std::unordered_map<std::pair<Node, bool>, Node, NodePolPairHashFunction>& |
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visited) const; |
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/** |
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* Apply prenexing aggressively. Returns the prenex normal form of n. |
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*/ |
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Node computePrenexAgg(Node n, std::map<Node, Node>& visited) const; |
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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 /* CVC5__THEORY__QUANTIFIERS__QUANTIFIERS_REWRITER_H */ |