net.sf.tweety.logics.pl.syntax

Class Negation

java.lang.Object

net.sf.tweety.logics.pl.syntax.PropositionalFormula

net.sf.tweety.logics.pl.syntax.Negation

All Implemented Interfaces:

net.sf.tweety.commons.Formula, net.sf.tweety.logics.commons.syntax.interfaces.ClassicalFormula, net.sf.tweety.logics.commons.syntax.interfaces.Conjuctable, net.sf.tweety.logics.commons.syntax.interfaces.Disjunctable, net.sf.tweety.logics.commons.syntax.interfaces.Invertable, net.sf.tweety.logics.commons.syntax.interfaces.ProbabilityAware, net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

public class Negation
extends PropositionalFormula

This class models classical negation of propositional logic.

Author:

Matthias Thimm, Tim Janus

Constructor Summary

Constructors

Constructor and Description
Negation(PropositionalFormula formula) Creates a new negation with the given formula.

Method Summary

Modifier and Type	Method and Description
PropositionalFormula	clone()
PropositionalFormula	collapseAssociativeFormulas() This method collapses all associative operations appearing in this term, e.g.
boolean	equals(Object obj)
Set<Proposition>	getAtoms()
PropositionalFormula	getFormula() Returns the formula within this negation.
Set<PropositionalFormula>	getLiterals() Returns all literals, i.e.
Set<PossibleWorld>	getModels(PropositionalSignature sig) Returns the set of models of this formula wrt.
Set<PropositionalPredicate>	getPredicates()
PropositionalSignature	getSignature()
int	hashCode()
boolean	hasLowerBindingPriority(PropositionalFormula other)
boolean	isLiteral()
int	numberOfOccurrences(Proposition p) Returns the number of occurrences of the given proposition within this formula
PropositionalFormula	replace(Proposition p, PropositionalFormula f, int i) Replaces the ith instance of the proposition p by f.
Conjunction	toCnf() This method returns this formula in conjunctive normal form (CNF).
PropositionalFormula	toNnf() This method returns this formula in negation normal form (NNF).
String	toString()
PropositionalFormula	trim() Removes duplicates (identical formulas) from conjunctions and disjunctions and duplicate negations.

Methods inherited from class net.sf.tweety.logics.pl.syntax.PropositionalFormula

combineWithAnd, combineWithOr, complement, getModels, getPredicateCls, getPrimeImplicants, getUniformProbability, isConjunctiveClause, resolvableWith, resolveWith, toBlakeCanonicalForm, toDnf

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Negation

public Negation(PropositionalFormula formula)

Creates a new negation with the given formula.

Parameters:

formula - the formula within the negation.

Method Detail

getFormula

public PropositionalFormula getFormula()

Returns the formula within this negation.

Returns:

the formula within this negation.

collapseAssociativeFormulas

public PropositionalFormula collapseAssociativeFormulas()

Description copied from class: PropositionalFormula

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 PropositionalFormula

Returns:

the collapsed formula.

hasLowerBindingPriority

public boolean hasLowerBindingPriority(PropositionalFormula other)

toString

public String toString()

Overrides:

toString in class Object

toNnf

public PropositionalFormula toNnf()

Description copied from class: PropositionalFormula

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 PropositionalFormula

Returns:

the formula in NNF.

trim

public PropositionalFormula trim()

Description copied from class: PropositionalFormula

Removes duplicates (identical formulas) from conjunctions and disjunctions and duplicate negations.

Specified by:

trim in class PropositionalFormula

Returns:

an equivalent formula without duplicates.

hashCode

public int hashCode()

Specified by:

hashCode in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

hashCode in class PropositionalFormula

equals

public boolean equals(Object obj)

Specified by:

equals in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

equals in class PropositionalFormula

getPredicates

public Set<PropositionalPredicate> getPredicates()

Specified by:

getPredicates in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

getPredicates in class PropositionalFormula

clone

public PropositionalFormula clone()

Specified by:

clone in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

clone in class PropositionalFormula

getAtoms

public Set<Proposition> getAtoms()

Specified by:

getAtoms in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

getAtoms in class PropositionalFormula

isLiteral

public boolean isLiteral()

Specified by:

isLiteral in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Overrides:

isLiteral in class PropositionalFormula

getLiterals

public Set<PropositionalFormula> getLiterals()

Description copied from class: PropositionalFormula

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 PropositionalFormula

Returns:

all literals appearing in this formula.

getSignature

public PropositionalSignature getSignature()

Specified by:

getSignature in interface net.sf.tweety.commons.Formula

Overrides:

getSignature in class PropositionalFormula

toCnf

public Conjunction toCnf()

Description copied from class: PropositionalFormula

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 PropositionalFormula

Returns:

the formula in CNF.

getModels

public Set<PossibleWorld> getModels(PropositionalSignature sig)

Description copied from class: PropositionalFormula

Returns the set of models of this formula wrt. the given signature.

Specified by:

getModels in class PropositionalFormula

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: PropositionalFormula

Returns the number of occurrences of the given proposition within this formula

Specified by:

numberOfOccurrences in class PropositionalFormula

Parameters:

p - some proposition

Returns:

the number of occurrences of the given proposition within this formula

replace

public PropositionalFormula replace(Proposition p,
                                    PropositionalFormula f,
                                    int i)

Description copied from class: PropositionalFormula

Replaces the ith instance of the proposition p by f.

Specified by:

replace in class PropositionalFormula

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.