net.sf.tweety.logics.rdl.syntax

Class DefaultRule

java.lang.Object

net.sf.tweety.logics.fol.syntax.RelationalFormula

net.sf.tweety.logics.rdl.syntax.DefaultRule

All Implemented Interfaces:

Formula, ClassicalFormula, ComplexLogicalFormula, Conjuctable, Disjunctable, Invertable, LogicStructure, ProbabilityAware, QuantifiedFormula, SimpleLogicalFormula

public class DefaultRule
extends RelationalFormula

Models a default rule 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 Summary

Fields

Modifier and Type	Field and Description
private FolFormula	conc The conclusion of the default rule
private java.util.Collection<FolFormula>	jus The justifications of the default rule
private FolFormula	pre The prerequisite of the default rule

Constructor Summary

Constructors

Constructor and Description
DefaultRule() an empty Default Rule
DefaultRule(FolFormula pre, java.util.Collection<FolFormula> jus, FolFormula conc)
DefaultRule(FolFormula pre, FolFormula jus, FolFormula conc)

Method Summary

Modifier and Type	Method and Description
RelationalFormula	clone() Creates a deep copy of this formula
Conjunction	combineWithAnd(Conjuctable formula) Returns a conjunction of this and the given formula.
Disjunction	combineWithOr(Disjunctable formula)
RelationalFormula	complement()
boolean	containsQuantifier() Checks whether this formula contains any quantification.
boolean	equals(java.lang.Object o)
java.util.Set<FOLAtom>	getAtoms() Processes the set of all atoms which appear in this formula
FolFormula	getConclusion()
java.util.Set<Functor>	getFunctors()
java.util.Collection<FolFormula>	getJustification()
java.util.Set<? extends Predicate>	getPredicates() Processes the set of all predicates which appear in this formula
FolFormula	getPrerequisite()
java.util.Set<Variable>	getQuantifierVariables()
FolSignature	getSignature() Returns the signature of the language of this formula.
java.util.Set<Term<?>>	getTerms()
<C extends Term<?>> java.util.Set<C>	getTerms(java.lang.Class<C> cls) Processes the set containing all terms of type C.
java.util.Set<Variable>	getUnboundVariables()
Probability	getUniformProbability()
int	hashCode()
boolean	isClosed() Checks whether this formula is closed, i.e.
boolean	isClosed(java.util.Set<Variable> boundVariables) Checks whether this formula is closed, i.e.
boolean	isLiteral()
boolean	isNormal(DefaultTheory dt) Tests, whether the default is normal normal ^= a:c/c
boolean	isWellBound() Checks whether this formula is well-bound, i.e.
boolean	isWellBound(java.util.Set<Variable> boundVariables) Checks whether this formula is well-bound, i.e.
RelationalFormula	substitute(Term<?> v, Term<?> t) Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula.
java.lang.String	toString()

Methods inherited from class net.sf.tweety.logics.fol.syntax.RelationalFormula

allGroundInstances, allSubstitutions, containsTermsOfType, exchange, getFormula, getPredicateCls, getSatisfactionRatio, isGround, isWellFormed, substitute

Methods inherited from class java.lang.Object

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

Field Detail

pre

private FolFormula pre

The prerequisite of the default rule

jus

private java.util.Collection<FolFormula> jus

The justifications of the default rule

conc

private FolFormula conc

The conclusion of the default rule

Constructor Detail

DefaultRule

public DefaultRule()

an empty Default Rule

DefaultRule

public DefaultRule(FolFormula pre,
                   FolFormula jus,
                   FolFormula conc)
            throws ParserException

Throws:

ParserException

DefaultRule

public DefaultRule(FolFormula pre,
                   java.util.Collection<FolFormula> jus,
                   FolFormula conc)
            throws ParserException

Throws:

ParserException

Method Detail

isNormal

public boolean isNormal(DefaultTheory dt)

Tests, whether the default is normal normal ^= a:c/c

getPrerequisite

public FolFormula getPrerequisite()

Returns:

the default's prerequisite

getJustification

public java.util.Collection<FolFormula> getJustification()

Returns:

the default's justification

getConclusion

public FolFormula getConclusion()

Returns:

the default's conclusion

getPredicates

public java.util.Set<? extends Predicate> getPredicates()

Description copied from interface: SimpleLogicalFormula

Processes the set of all predicates which appear in this formula

Returns:

all predicates that appear in this formula

isLiteral

public boolean isLiteral()

Returns:

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

getQuantifierVariables

public java.util.Set<Variable> getQuantifierVariables()

Returns:

a set containing all quantified variables

getUnboundVariables

public java.util.Set<Variable> getUnboundVariables()

Returns:

a set of of unbound variables

containsQuantifier

public boolean containsQuantifier()

Description copied from interface: QuantifiedFormula

Checks whether this formula contains any quantification.

Returns:

"true" if this formula contains a quantification.

isWellBound

public boolean isWellBound()

Description copied from interface: QuantifiedFormula

Checks whether this formula is well-bound, i.e. whether no variable bound by a quantifier is again bound by another quantifier within the first quantifier's range.

Returns:

"true" if this formula is well-bound, "false" otherwise.

isWellBound

public boolean isWellBound(java.util.Set<Variable> boundVariables)

Description copied from interface: QuantifiedFormula

Checks whether this formula is well-bound, i.e. whether no variable bound by a quantifier is again bound by another quantifier within the first quantifier range. Every variable in "boundVariables" is assumed to be bound already.

Parameters:

boundVariables - the variables assumed to be bound.

Returns:

"true" if this formula is well-bound, "false" otherwise.

isClosed

public boolean isClosed()

Description copied from interface: QuantifiedFormula

Checks whether this formula is closed, i.e. whether every variables occurring in the formula is bound by a quantifier.

Returns:

"true" if this formula is closed, "false" otherwise.

isClosed

public boolean isClosed(java.util.Set<Variable> boundVariables)

Description copied from interface: QuantifiedFormula

Checks whether this formula is closed, i.e. whether every variables occurring in the formula is bound by a quantifier. Every variable in "boundVariables" is already assumed to be bound.

Parameters:

boundVariables - the variables assumed to be bound.

Returns:

"true" if this formula is closed wrt. "boundVariables", "false" otherwise.

getTerms

public java.util.Set<Term<?>> getTerms()

Returns:

a set containing all terms of this logical structure

getTerms

public <C extends Term<?>> java.util.Set<C> getTerms(java.lang.Class<C> cls)

Description copied from interface: LogicStructure

Processes the set containing all terms of type C. This method uses the equals method of the given Class and therefore does not add terms which are sub classes of type C to the set.

Parameters:

cls - The Class structure containing type information about the searched term

Returns:

A set containing all terms of type C of this logical structure

getAtoms

public java.util.Set<FOLAtom> 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 RelationalFormula

Returns:

all atoms that appear in this formula.

getFunctors

public java.util.Set<Functor> getFunctors()

Specified by:

getFunctors in class RelationalFormula

Returns:

all functor that appear in this formula.

substitute

public RelationalFormula substitute(Term<?> v,
                                    Term<?> t)
                             throws java.lang.IllegalArgumentException

Description copied from class: RelationalFormula

Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula. NOTE: if "v" is a variable and bound to a quantifier then "v" is not substituted in that quantifiers inner formula.

Specified by:

substitute in interface ComplexLogicalFormula

Specified by:

substitute in class RelationalFormula

Parameters:

v - the term to be substituted.

t - the term to substitute.

Returns:

a formula where every occurrence of "v" is replaced by "t".

Throws:

java.lang.IllegalArgumentException - if "v" and "t" are of different sorts (NOTE: this exception is only thrown when "v" actually appears in this formula).

getUniformProbability

public Probability getUniformProbability()

Specified by:

getUniformProbability in interface ProbabilityAware

Specified by:

getUniformProbability in class RelationalFormula

Returns:

this formula's probability in the uniform distribution.

complement

public RelationalFormula complement()

Specified by:

complement in interface Invertable

Specified by:

complement in class RelationalFormula

Returns:

the complement of this formula.

combineWithOr

public Disjunction combineWithOr(Disjunctable formula)

Specified by:

combineWithOr in interface Disjunctable

Specified by:

combineWithOr in class RelationalFormula

Parameters:

formula - a formula to be combined with OR and this.

Returns:

a disjunction of this and the given formula.

combineWithAnd

public Conjunction combineWithAnd(Conjuctable formula)

Description copied from interface: Conjuctable

Returns a conjunction of this and the given formula.

Specified by:

combineWithAnd in interface Conjuctable

Specified by:

combineWithAnd in class RelationalFormula

Parameters:

formula - a formula to be combined with AND and this.

Returns:

a conjunction of this and the given formula.

getSignature

public FolSignature 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 RelationalFormula

Returns:

the signature of the language of this formula.

toString

public java.lang.String toString()

Specified by:

toString in class RelationalFormula

clone

public RelationalFormula clone()

Description copied from interface: SimpleLogicalFormula

Creates a deep copy of this formula

Specified by:

clone in interface ComplexLogicalFormula

Specified by:

clone in interface SimpleLogicalFormula

Specified by:

clone in class RelationalFormula

hashCode

public int hashCode()

Specified by:

hashCode in interface SimpleLogicalFormula

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in interface SimpleLogicalFormula

Overrides:

equals in class java.lang.Object