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/********************* */
/*! \file inference_generator.h
** \verbatim
** Top contributors (to current version):
** Mudathir Mohamed, Andrew Reynolds
** This file is part of the CVC4 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.\endverbatim
**
** \brief Inference generator utility
**/
#include "cvc4_private.h"
#ifndef CVC4__THEORY__BAGS__INFERENCE_GENERATOR_H
#define CVC4__THEORY__BAGS__INFERENCE_GENERATOR_H
#include <map>
#include <vector>
#include "expr/node.h"
#include "infer_info.h"
#include "theory/bags/inference_manager.h"
#include "theory/bags/solver_state.h"
namespace CVC4 {
namespace theory {
namespace bags {
/**
* An inference generator class. This class is used by the core solver to
* generate lemmas
*/
class InferenceGenerator
{
public:
InferenceGenerator(SolverState* state, InferenceManager* im);
/**
* @param A is a bag of type (Bag E)
* @param e is a node of type E
* @return an inference that represents the following implication
* (=>
* true
* (>= (bag.count e A) 0)
*/
InferInfo nonNegativeCount(Node n, Node e);
/**
* @param n is (bag x c) of type (Bag E)
* @param e is a node of type E
* @return an inference that represents the following implication
* (=>
* true
* (= (bag.count e skolem) c))
* if e is exactly node x. Node skolem is a fresh variable equals (bag x c).
* Otherwise the following inference is returned
* (=>
* true
* (= (bag.count e skolem) (ite (= e x) c 0)))
*/
InferInfo mkBag(Node n, Node e);
/**
* @param n is (= A B) where A, B are bags of type (Bag E), and
* (not (= A B)) is an assertion in the equality engine
* @return an inference that represents the following implication
* (=>
* (not (= A B))
* (not (= (count e A) (count e B))))
* where e is a fresh skolem of type E.
*/
InferInfo bagDisequality(Node n);
/**
* @param n is (as emptybag (Bag E))
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (= 0 (count e skolem)))
* where skolem = (as emptybag (Bag String))
*/
InferInfo empty(Node n, Node e);
/**
* @param n is (union_disjoint A B) where A, B are bags of type (Bag E)
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (= (count e skolem)
* (+ (count e A) (count e B))))
* where skolem is a fresh variable equals (union_disjoint A B)
*/
InferInfo unionDisjoint(Node n, Node e);
/**
* @param n is (union_disjoint A B) where A, B are bags of type (Bag E)
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (=
* (count e skolem)
* (ite
* (> (count e A) (count e B))
* (count e A)
* (count e B)))))
* where skolem is a fresh variable equals (union_max A B)
*/
InferInfo unionMax(Node n, Node e);
/**
* @param n is (intersection_min A B) where A, B are bags of type (Bag E)
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (=
* (count e skolem)
* (ite(
* (< (count e A) (count e B))
* (count e A)
* (count e B)))))
* where skolem is a fresh variable equals (intersection_min A B)
*/
InferInfo intersection(Node n, Node e);
/**
* @param n is (difference_subtract A B) where A, B are bags of type (Bag E)
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (=
* (count e skolem)
* (ite
* (>= (count e A) (count e B))
* (- (count e A) (count e B))
* 0))))
* where skolem is a fresh variable equals (difference_subtract A B)
*/
InferInfo differenceSubtract(Node n, Node e);
/**
* @param n is (difference_remove A B) where A, B are bags of type (Bag E)
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (=
* (count e skolem)
* (ite
* (= (count e B) 0)
* (count e A)
* 0))))
* where skolem is a fresh variable equals (difference_remove A B)
*/
InferInfo differenceRemove(Node n, Node e);
/**
* @param n is (duplicate_removal A) where A is a bag of type (Bag E)
* @param e is a node of Type E
* @return an inference that represents the following implication
* (=>
* true
* (=
* (count e skolem)
* (ite (>= (count e A) 1) 1 0))))
* where skolem is a fresh variable equals (duplicate_removal A)
*/
InferInfo duplicateRemoval(Node n, Node e);
/**
* @param element of type T
* @param bag of type (bag T)
* @return a count term (bag.count element bag)
*/
Node getMultiplicityTerm(Node element, Node bag);
private:
/** generate skolem variable for node n and add it to inferInfo */
Node getSkolem(Node& n, InferInfo& inferInfo);
NodeManager* d_nm;
SkolemManager* d_sm;
SolverState* d_state;
/** Pointer to the inference manager */
InferenceManager* d_im;
/** Commonly used constants */
Node d_true;
Node d_zero;
Node d_one;
};
} // namespace bags
} // namespace theory
} // namespace CVC4
#endif /* CVC4__THEORY__BAGS__INFERENCE_GENERATOR_H */
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