net.sf.tweety.logics.fol.semantics

Class HerbrandBase

java.lang.Object

net.sf.tweety.logics.fol.semantics.HerbrandBase

public class HerbrandBase
extends java.lang.Object

The Herbrand base is the set of all possible ground atoms of some given first-order logic.
NOTE: We only allow to define a Herbrand base for signatures without function symbols.

Author:

Matthias Thimm

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Set<FOLAtom>	atoms The atoms of this Herbrand base.

Constructor Summary

Constructors

Constructor and Description
HerbrandBase(FolSignature sig) Creates a new Herbrand base for the given signature.

Method Summary

Modifier and Type	Method and Description
java.util.Set<HerbrandInterpretation>	allHerbrandInterpretations() Computes all possible Herbrand interpretations of this Herbrand base, i.e.
private java.util.Set<FOLAtom>	getAllInstantiations(FolSignature sig, Predicate p, java.util.List<Term<?>> arguments) Computes all instantiations of the predicate "p" relative to the signature "sig" where "arguments" defines the first arguments of the atoms.
java.util.Set<FOLAtom>	getAtoms() Returns all atoms of this Herbrand base.

Methods inherited from class java.lang.Object

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

Field Detail

atoms

private java.util.Set<FOLAtom> atoms

The atoms of this Herbrand base.

Constructor Detail

HerbrandBase

public HerbrandBase(FolSignature sig)
             throws java.lang.IllegalArgumentException

Creates a new Herbrand base for the given signature.
NOTE: We only allow to define a Herbrand base for signatures without function symbols.

Parameters:

sig - the underlying first-order signature for this Herbrand base. There should be no functors defined in "sig"

Throws:

IllegalArgumentationException - if "sig" contains a functor.

java.lang.IllegalArgumentException

Method Detail

getAllInstantiations

private java.util.Set<FOLAtom> getAllInstantiations(FolSignature sig,
                                                    Predicate p,
                                                    java.util.List<Term<?>> arguments)

Computes all instantiations of the predicate "p" relative to the signature "sig" where "arguments" defines the first arguments of the atoms.

Parameters:

sig - a signature for which the instantiations should be computed.

p - the predicate of the atoms.

arguments - the currently set arguments of the atoms.

Returns:

the complete set of instantiations of "p" relative to "sig" and "arguments".

allHerbrandInterpretations

public java.util.Set<HerbrandInterpretation> allHerbrandInterpretations()

Computes all possible Herbrand interpretations of this Herbrand base, i.e. all possible subsets of this Herbrand base.

Returns:

all possible Herbrand interpretations of this Herbrand base, i.e. all possible subsets of this Herbrand base.

getAtoms

public java.util.Set<FOLAtom> getAtoms()

Returns all atoms of this Herbrand base.

Returns:

all atoms of this Herbrand base.