Package org.tweetyproject.logics.rdl.syntax

Class DefaultRule

java.lang.Object

org.tweetyproject.logics.commons.syntax.RelationalFormula

org.tweetyproject.logics.rdl.syntax.DefaultRule

All Implemented Interfaces:

Formula, ClassicalFormula, ComplexLogicalFormula, Conjunctable, 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

Constructor Summary

Constructors

Constructor	Description
DefaultRule()	an empty Default Rule
DefaultRule(FolFormula pre, Collection<FolFormula> jus, FolFormula conc)	Creates a new DefaultRule
DefaultRule(FolFormula pre, FolFormula jus, FolFormula conc)	Creates a new DefaultRule

Method Summary

Modifier and Type	Method	Description
RelationalFormula	clone()	Creates a deep copy of this formula
Conjunction	combineWithAnd(Conjunctable 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(Object o)
Set<FolAtom>	getAtoms()	Processes the set of all atoms which appear in this formula
FolFormula	getConclusion()	Return the default's conclusion
Set<Functor>	getFunctors()
Collection<FolFormula>	getJustification()	Return the default's justification
Set<? extends Predicate>	getPredicates()	Processes the set of all predicates which appear in this formula
FolFormula	getPrerequisite()	Return the default's prerequisite
Set<Variable>	getQuantifierVariables()
FolSignature	getSignature()	Returns the signature of the language of this formula.
Set<Term<?>>	getTerms()
<C extends Term<?>> Set<C>	getTerms(Class<C> cls)	Processes the set containing all terms of type C.
Set<Variable>	getUnboundVariables()
Probability	getUniformProbability()
int	hashCode()
boolean	isClosed()	Checks whether this formula is closed, i.e.
boolean	isClosed(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(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.
String	toString()

Methods inherited from class org.tweetyproject.logics.commons.syntax.RelationalFormula

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Details

DefaultRule

public DefaultRule()

an empty Default Rule

DefaultRule

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

Creates a new DefaultRule

Parameters:

pre - the prerequsite

jus - the justification

conc - the conclusion

Throws:

IllegalArgumentException - if there is some issue with the arguments

ParserException - when a parameter is missing

DefaultRule

public DefaultRule(FolFormula pre,
 Collection<FolFormula> jus,
 FolFormula conc)
            throws IllegalArgumentException

Creates a new DefaultRule

Parameters:

pre - the prerequsite

jus - the justifications

conc - the conclusion

Throws:

IllegalArgumentException - if there is some issue with the arguments

Method Details

isNormal

public boolean isNormal(DefaultTheory dt)

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

Parameters:

dt - a default theory

Returns:

true iff the theory is normal

getPrerequisite

public FolFormula getPrerequisite()

Return the default's prerequisite

Returns:

the default's prerequisite

getJustification

public Collection<FolFormula> getJustification()

Return the default's justification

Returns:

the default's justification

getConclusion

public FolFormula getConclusion()

Return the default's conclusion

Returns:

the default's conclusion

getPredicates

public 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 Set<Variable> getQuantifierVariables()

Returns:

a set containing all quantified variables

getUnboundVariables

public 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(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(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 Set<Term<?>> getTerms()

Returns:

a set containing all terms of this logical structure

getTerms

public <C extends Term<?>> Set<C> getTerms(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.

Type Parameters:

C - the type of terms

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 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 Set<Functor> getFunctors()

Specified by:

getFunctors in class RelationalFormula

Returns:

all functors that appear in this formula.

substitute

public RelationalFormula substitute(Term<?> v,
 Term<?> t)
                             throws 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:

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(Conjunctable formula)

Description copied from interface: Conjunctable

Returns a conjunction of this and the given formula.

Specified by:

combineWithAnd in interface Conjunctable

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.

Returns:

the signature of the language of this formula.

toString

public 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

Returns:

the cloned formula

hashCode

public int hashCode()

Specified by:

hashCode in interface SimpleLogicalFormula

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Specified by:

equals in interface SimpleLogicalFormula

Overrides:

equals in class Object