Package net.sf.tweety.logics.pl.syntax

Class Implication

    • Constructor Detail

      • Implication

        public Implication​(PlFormula a,
                   PlFormula b)
        Creates a new implication a=>b with the two given formulas
        Parameters:
        a - a propositional formula.
        b - a propositional formula.

      • Implication

        public Implication​(Pair<PlFormula,​PlFormula> formulas)
        Creates a new implication 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 implication.
        Returns:
        the formulas that are part of the implication

      • setFormulas

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

      • setFormulas

        public void setFormulas​(PlFormula left,
                        PlFormula right)
        Sets the formulas of the implication.
        Parameters:
        left -
        right -

      • setFirstFormula

        public void setFirstFormula​(PlFormula left)
        Sets the left side formula of the implication left => right.
        Parameters:
        left - formula

      • setSecondFormula

        public void setSecondFormula​(PlFormula right)
        Sets the right side formula of the implication left => right
        Parameters:
        right - 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.
        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.