Class Equivalence

    • Constructor Detail

      • Equivalence

        public Equivalence​(PlFormula a,
                           PlFormula b)
        Creates a new equivalence with the given two formulas
        Parameters:
        a - a propositional formula
        b - a propositional formula
      • Equivalence

        public Equivalence​(Pair<PlFormula,​PlFormula> formulas)
        Creates a new equivalence with the given pair of formulas
        Parameters:
        formulas - a pair of formulas
    • Method Detail

      • getFormulas

        public Pair<PlFormula,​PlFormula> getFormulas()
        Returns the formulas of the equivalence.
        Returns:
        the formulas that are part of the equivalence
      • setFormulas

        public void setFormulas​(Pair<PlFormula,​PlFormula> formulas)
        Sets the formulas of the equivalence.
        Parameters:
        formulas - the formulas
      • setFormulas

        public void setFormulas​(PlFormula formula1,
                                PlFormula formula2)
        Sets the formulas of the equivalence.
        Parameters:
        formula1 - some formula
        formula2 - some formula
      • getLiterals

        public java.util.Set<PlFormula> getLiterals()
        Description copied from class: PlFormula
        Returns all literals, i.e. all formulas of the form "a" or "!a" where "a" is a proposition, that appear in this formula.
        Specified by:
        getLiterals in class PlFormula
        Returns:
        all literals appearing in this formula.
      • collapseAssociativeFormulas

        public PlFormula collapseAssociativeFormulas()
        Description copied from class: PlFormula
        This method collapses all associative operations appearing in this term, e.g. every a||(b||c) becomes a||b||c.
        Specified by:
        collapseAssociativeFormulas in class PlFormula
        Returns:
        the collapsed formula.
      • trim

        public PlFormula trim()
        Description copied from class: PlFormula
        Removes duplicates (identical formulas) from conjunctions and disjunctions and removes duplicate negations. Simplifies equivalences and implications with equivalent formulas (A=>A, A<=>A) to tautologies.
        Specified by:
        trim in class PlFormula
        Returns:
        an equivalent formula without duplicates.
      • toNnf

        public PlFormula toNnf()
        Description copied from class: PlFormula
        This method returns this formula in negation normal form (NNF). A formula is in NNF iff negations occur only directly in front of a proposition.
        Specified by:
        toNnf in class PlFormula
        Returns:
        the formula in NNF.
      • toCnf

        public Conjunction toCnf()
        Description copied from class: PlFormula
        This method returns this formula in conjunctive normal form (CNF). A formula is in CNF iff it is a conjunction of disjunctions and in NNF. The CNF generated by this method is not necessarily minimal.
        Specified by:
        toCnf in class PlFormula
        Returns:
        the formula in CNF.
      • getModels

        public java.util.Set<PossibleWorld> getModels​(PlSignature sig)
        Description copied from class: PlFormula
        Returns the set of models of this formula wrt. the given signature.
        Specified by:
        getModels in class PlFormula
        Parameters:
        sig - some propositional signature
        Returns:
        the set of models of this formula wrt. the given signature.
      • numberOfOccurrences

        public int numberOfOccurrences​(Proposition p)
        Description copied from class: PlFormula
        Returns the number of occurrences of the given proposition within this formula
        Specified by:
        numberOfOccurrences in class PlFormula
        Parameters:
        p - some proposition
        Returns:
        the number of occurrences of the given proposition within this formula
      • replace

        public PlFormula replace​(Proposition p,
                                 PlFormula f,
                                 int i)
        Description copied from class: PlFormula
        Replaces the ith instance of the proposition p by f.
        Specified by:
        replace in class PlFormula
        Parameters:
        p - some proposition
        f - some formula
        i - the index of the proposition
        Returns:
        a new formula with the ith instance of the proposition p replaced by f.
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
      • getSignature

        public PlSignature getSignature()
        Description copied from interface: Formula
        Returns the signature of the language of this formula.
        Specified by:
        getSignature in interface Formula
        Overrides:
        getSignature in class PlFormula
        Returns:
        the signature of the language of this formula.