Package org.tweetyproject.logics.pl.syntax

Class Proposition

java.lang.Object
org.tweetyproject.logics.pl.syntax.PlFormula
org.tweetyproject.logics.pl.syntax.Proposition
All Implemented Interfaces:
Comparable<Proposition>, Formula, Atom, ClassicalFormula, Conjunctable, Disjunctable, Invertable, ProbabilityAware, SimpleLogicalFormula
Direct Known Subclasses:
QueryProposition
public class Proposition extends PlFormula implements Atom, Comparable<Proposition>
This class represents a simple proposition in propositional logic.
Author:
Matthias Thimm, Tim Janus

  • Constructor Details

    • Proposition

      public Proposition()
      Default-Ctor for dynamic instantiation

    • Proposition

      public Proposition(String name)
      Creates a new proposition of the given name.
      Parameters:
      name - the name of the proposition.

    • Proposition

      public Proposition(Proposition other)
      constructor
      Parameters:
      other - another proposition

  • Method Details

    • getName

      public String getName()
      Specified by:
      getName in interface Atom
      Returns:
      the name of this proposition.

    • getPredicate

      public PlPredicate getPredicate()
      Specified by:
      getPredicate in interface Atom
      Returns:
      the predicate of the atom

    • getPredicates

      public Set<PlPredicate> getPredicates()
      Description copied from interface: SimpleLogicalFormula
      Processes the set of all predicates which appear in this formula
      Specified by:
      getPredicates in interface SimpleLogicalFormula
      Specified by:
      getPredicates in class PlFormula
      Returns:
      all predicates that appear in this formula

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • 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.

    • 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.

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface SimpleLogicalFormula
      Specified by:
      hashCode in class PlFormula

    • equals

      public boolean equals(Object obj)
      Specified by:
      equals in interface SimpleLogicalFormula
      Specified by:
      equals in class PlFormula

    • 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.

    • clone

      public Proposition clone()
      Description copied from interface: SimpleLogicalFormula
      Creates a deep copy of this formula
      Specified by:
      clone in interface SimpleLogicalFormula
      Specified by:
      clone in class PlFormula
      Returns:
      the cloned 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.

    • addArgument

      public void addArgument(Term<?> arg)
      Description copied from interface: Atom
      Adds an argument to the atom's argument list
      Specified by:
      addArgument in interface Atom
      Parameters:
      arg - The next argument

    • getArguments

      public List<? extends Term<?>> getArguments()
      Specified by:
      getArguments in interface Atom
      Returns:
      A list containing all the arguments of this specific atom

    • isComplete

      public boolean isComplete()
      Specified by:
      isComplete in interface Atom
      Returns:
      true if the size of the argument list is equal to the arity of the predicate

    • getAtoms

      public Set<Proposition> getAtoms()
      Description copied from interface: SimpleLogicalFormula
      Processes the set of all atoms which appear in this formula
      Specified by:
      getAtoms in interface SimpleLogicalFormula
      Specified by:
      getAtoms in class PlFormula
      Returns:
      The set of all atoms

    • isLiteral

      public boolean isLiteral()
      Specified by:
      isLiteral in interface SimpleLogicalFormula
      Overrides:
      isLiteral in class PlFormula
      Returns:
      true if the formula represents a literal in the language or false otherwise

    • getLiterals

      public 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.

    • setPredicate

      public Atom.RETURN_SET_PREDICATE setPredicate(Predicate predicate)
      Description copied from interface: Atom
      Changes the predicate of the atom. Given an old Predicate po and a new predicate pn with their list of arguments types at(po) and at(pn) and the arguments of this Atom: arg(this) this method distinguishes between three cases: 1. The predicate only differ in the names, returning RSP_SUCCESS 2. The old predicates argument types is a sub-list of the new argument types then the method returns RSP_INCOMPLETE and the atoms isComplete() method returns false 3. The new predicates argument types is a sub-list of the old argument types then the method returns RSP_TRUNCATED and the arguments of this atom are truncated too and isComplete() returns true. 4. The old and new predicates' argument types differ then the list of arguments of the atom get cleared and isComplete() returns false.
      Specified by:
      setPredicate in interface Atom
      Parameters:
      predicate - some predicate
      Returns:
      Depends on the cases described above: 1. RSP_SUCCESS 2. RSP_INCOMPLETE 3. RSP_TRUNCATED 4. RSP_CLEARED

    • compareTo

      public int compareTo(Proposition o)
      Specified by:
      compareTo in interface Comparable<Proposition>

    • 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.

    • 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.

    • getModels

      public 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.