Package net.sf.tweety.logics.rdl.syntax

Class DefaultTheory

  • All Implemented Interfaces:
    BeliefBase
    public class DefaultTheory
extends java.lang.Object
implements BeliefBase
    Models a default theory in Reiter's default logic, see [R. Reiter. A logic for default reasoning. Artificial Intelligence, 13:81–132, 1980].
    Author:
    Matthias Thimm, Nils Geilen

    • Field Detail

      • facts

        private FolBeliefSet facts
        The set of facts (first-order formulas).

      • defaults

        private java.util.Collection<DefaultRule> defaults
        The set of default rules

    • Constructor Detail

      • DefaultTheory

        public DefaultTheory()
        constructs empty default theory

      • DefaultTheory

        public DefaultTheory​(FolBeliefSet facts,
                     java.util.Collection<DefaultRule> defaults)
        constructs a default theory from a knowledge base and a set of defaults
        Parameters:
        facts - the knowledge base
        defaults - the defaults

    • Method Detail

      • addFact

        void addFact​(FolFormula fact)
        add facts to knowledge base
        Parameters:
        fact - some fol formula

      • removeFact

        void removeFact​(FolFormula fact)
        removes fact from knowledge base
        Parameters:
        fact - some fol formula

      • addDefault

        void addDefault​(DefaultRule d)
        adds default rule
        Parameters:
        d - a default rule

      • removeDefault

        void removeDefault​(DefaultRule d)
        removes default rule
        Parameters:
        d - a default rule

      • getDefaults

        public java.util.Collection<DefaultRule> getDefaults()
        Returns:
        all the default rules

      • ground

        public DefaultTheory ground()
        Removes Variables by expanding formulas
        Returns:
        grounded version of the default theory

      • getMinimalSignature

        public Signature getMinimalSignature()
        Description copied from interface: BeliefBase
        Returns the signature of the language of this knowledge base.
        Specified by:
        getMinimalSignature in interface BeliefBase
        Returns:
        the signature of the language of this knowledge base.

      • toString

        public java.lang.String toString()
        Specified by:
        toString in interface BeliefBase
        Overrides:
        toString in class java.lang.Object

      • getFacts

        public FolBeliefSet getFacts()
        Returns:
        FoL formulas in default theories