net.sf.tweety.logics.pl.syntax

Class Proposition

java.lang.Object

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

net.sf.tweety.logics.pl.syntax.Proposition

All Implemented Interfaces:

java.lang.Comparable<Proposition>, Formula, Atom, ClassicalFormula, Conjuctable, Disjunctable, Invertable, ProbabilityAware, SimpleLogicalFormula

Direct Known Subclasses:

QueryProposition

public class Proposition
extends PropositionalFormula
implements Atom, java.lang.Comparable<Proposition>

This class represents a simple proposition in propositional logic.

Author:

Matthias Thimm, Tim Janus

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.tweety.logics.commons.syntax.interfaces.Atom

Atom.AtomImpl, Atom.RETURN_SET_PREDICATE

Field Summary

Fields

Modifier and Type	Field and Description
private PropositionalPredicate	predicate The name of the proposition

Constructor Summary

Constructors

Constructor and Description
Proposition() Default-Ctor for dynamic instantiation
Proposition(Proposition other)
Proposition(java.lang.String name) Creates a new proposition of the given name.

Method Summary

Modifier and Type	Method and Description
void	addArgument(Term<?> arg) Adds an argument to the atom's argument list
Proposition	clone() Creates a deep copy of this formula
PropositionalFormula	collapseAssociativeFormulas() This method collapses all associative operations appearing in this term, e.g.
int	compareTo(Proposition o)
boolean	equals(java.lang.Object obj)
java.util.List<? extends Term<?>>	getArguments()
java.util.Set<Proposition>	getAtoms() Processes the set of all atoms which appear in this formula
java.util.Set<PropositionalFormula>	getLiterals() Returns all literals, i.e.
java.util.Set<PossibleWorld>	getModels(PropositionalSignature sig) Returns the set of models of this formula wrt.
java.lang.String	getName()
PropositionalPredicate	getPredicate()
java.util.Set<PropositionalPredicate>	getPredicates() Processes the set of all predicates which appear in this formula
PropositionalSignature	getSignature() Returns the signature of the language of this formula.
int	hashCode()
boolean	isComplete()
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.
Atom.RETURN_SET_PREDICATE	setPredicate(Predicate predicate) Changes the predicate of the atom.
Conjunction	toCnf() This method returns this formula in conjunctive normal form (CNF).
PropositionalFormula	toNnf() This method returns this formula in negation normal form (NNF).
java.lang.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

Methods inherited from interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

getPredicateCls

Field Detail

predicate

private PropositionalPredicate predicate

The name of the proposition

Constructor Detail

Proposition

public Proposition()

Default-Ctor for dynamic instantiation

Proposition

public Proposition(java.lang.String name)

Creates a new proposition of the given name.

Parameters:

name - the name of the proposition.

Proposition

public Proposition(Proposition other)

Method Detail

getName

public java.lang.String getName()

Specified by:

getName in interface Atom

Returns:

the name of this proposition.

getPredicate

public PropositionalPredicate getPredicate()

Specified by:

getPredicate in interface Atom

Returns:

the predicate of the atom

getPredicates

public java.util.Set<PropositionalPredicate> 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 PropositionalFormula

Returns:

all predicates that appear in this formula

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

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.

getSignature

public PropositionalSignature 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 PropositionalFormula

Returns:

the signature of the language of this formula.

hashCode

public int hashCode()

Specified by:

hashCode in interface SimpleLogicalFormula

Specified by:

hashCode in class PropositionalFormula

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface SimpleLogicalFormula

Specified by:

equals in class PropositionalFormula

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.

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 PropositionalFormula

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.

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 java.util.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 java.util.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 PropositionalFormula

Returns:

The set of all atoms

isLiteral

public boolean isLiteral()

Specified by:

isLiteral in interface SimpleLogicalFormula

Overrides:

isLiteral in class PropositionalFormula

Returns:

true if the formula represents a literal in the language or false otherwise

getLiterals

public java.util.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.

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

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 java.lang.Comparable<Proposition>

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.

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.

getModels

public java.util.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.