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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds
*
* This file is part of the cvc5 project.
*
* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
* in the top-level source directory and their institutional affiliations.
* All rights reserved. See the file COPYING in the top-level source
* directory for licensing information.
* ****************************************************************************
*
* Preprocessor for the theory of quantifiers.
*/
#include "cvc5_private.h"
#ifndef CVC5__THEORY__QUANTIFIERS__QUANTIFIERS_PREPROCESS_H
#define CVC5__THEORY__QUANTIFIERS__QUANTIFIERS_PREPROCESS_H
#include "proof/trust_node.h"
#include "smt/env_obj.h"
namespace cvc5 {
namespace theory {
namespace quantifiers {
/**
* Module for doing preprocessing that is pertinent to quantifiers. These
* operations cannot be done in the rewriter since e.g. preskolemization
* depends on knowing the polarity of the position in which quantifiers occur.
*/
class QuantifiersPreprocess : protected EnvObj
{
public:
QuantifiersPreprocess(Env& env);
/** preprocess
*
* This returns the result of applying simple quantifiers-specific
* pre-processing to n, including but not limited to:
* - pre-skolemization,
* - aggressive prenexing.
* The argument isInst is set to true if n is an instance of a previously
* registered quantified formula. If this flag is true, we do not apply
* certain steps like pre-skolemization since we know they will have no
* effect.
*
* The result is wrapped in a trust node of kind TrustNodeKind::REWRITE.
*/
TrustNode preprocess(Node n, bool isInst = false) const;
private:
using NodePolPairHashFunction = PairHashFunction<Node, bool, std::hash<Node>>;
/**
* Pre-skolemize quantifiers. Return the pre-skolemized form of n.
*
* @param n The formula to preskolemize.
* @param polarity The polarity of n in the input.
* @param fvs The free variables
* @param visited Cache of visited (node, polarity) pairs.
*/
Node preSkolemizeQuantifiers(
Node n,
bool polarity,
std::vector<TNode>& fvs,
std::unordered_map<std::pair<Node, bool>, Node, NodePolPairHashFunction>&
visited) const;
/**
* Apply prenexing aggressively. Returns the prenex normal form of n.
*/
Node computePrenexAgg(Node n, std::map<Node, Node>& visited) const;
};
} // namespace quantifiers
} // namespace theory
} // namespace cvc5
#endif /* CVC5__THEORY__QUANTIFIERS__QUANTIFIERS_REWRITER_H */
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