net.sf.tweety.logics.fol.syntax

Class SpecialFormula

java.lang.Object

net.sf.tweety.logics.commons.syntax.RelationalFormula

net.sf.tweety.logics.fol.syntax.FolFormula

net.sf.tweety.logics.fol.syntax.SpecialFormula

All Implemented Interfaces:

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

Direct Known Subclasses:

Contradiction, Tautology

public abstract class SpecialFormula
extends FolFormula

This class captures the common functionalities of the special formulas tautology and contradiction.

Author:

Matthias Thimm

Constructor Summary

Constructors

Constructor and Description
SpecialFormula()

Method Summary

Modifier and Type	Method and Description
FolFormula	collapseAssociativeFormulas() This method collapses all associative operations appearing in this term, e.g.
boolean	containsQuantifier() Checks whether this formula contains any quantification.
java.util.Set<FOLAtom>	getAtoms() Processes the set of all atoms which appear in this formula
java.util.Set<Conjunction>	getConjunctions()
java.util.Set<Disjunction>	getDisjunctions()
java.util.Set<Functor>	getFunctors()
java.util.Set<Predicate>	getPredicates() Processes the set of all predicates which appear in this formula
java.util.Set<FolFormula>	getQuantifiedFormulas()
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()
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	isDnf() Checks whether this formula is in disjunctive normal form.
boolean	isLiteral()
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.
FolFormula	substitute(Term<?> v, Term<?> t) Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula.
FolFormula	toNnf() Makes the negation normal form of this formula.

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

clone, combineWithAnd, combineWithOr, complement, getQuantifierVariables, getSignature, getUniformProbability, toDnf

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

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

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

equals, hashCode

Constructor Detail

SpecialFormula

public SpecialFormula()

Method Detail

containsQuantifier

public boolean containsQuantifier()

Description copied from interface: QuantifiedFormula

Checks whether this formula contains any quantification.

Returns:

"true" if this formula contains a quantification.

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.

getPredicates

public java.util.Set<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

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.

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.

isLiteral

public boolean isLiteral()

Returns:

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

substitute

public FolFormula substitute(Term<?> v,
                             Term<?> t)

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 FolFormula

Parameters:

v - the term to be substituted.

t - the term to substitute.

Returns:

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

getUnboundVariables

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

Returns:

a set of of unbound variables

getFunctors

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

Specified by:

getFunctors in class RelationalFormula

Returns:

all functors that appear in this formula.

getQuantifiedFormulas

public java.util.Set<FolFormula> getQuantifiedFormulas()

getDisjunctions

public java.util.Set<Disjunction> getDisjunctions()

getConjunctions

public java.util.Set<Conjunction> getConjunctions()

isDnf

public boolean isDnf()

Description copied from class: FolFormula

Checks whether this formula is in disjunctive normal form.

Specified by:

isDnf in class FolFormula

Returns:

"true" iff this formula is in disjunctive normal form.

toNnf

public FolFormula toNnf()

Description copied from class: FolFormula

Makes the negation normal form of this formula.

Specified by:

toNnf in class FolFormula

Returns:

the NNF of this formula

collapseAssociativeFormulas

public FolFormula collapseAssociativeFormulas()

Description copied from class: FolFormula

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 FolFormula

Returns:

the collapsed formula.