net.sf.tweety.logics.rcl.reasoner

Class SimpleRelationalCReasoner

java.lang.Object

net.sf.tweety.logics.rcl.reasoner.SimpleRelationalCReasoner

All Implemented Interfaces:

net.sf.tweety.commons.ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>, net.sf.tweety.commons.QualitativeReasoner<RclBeliefSet,net.sf.tweety.logics.fol.syntax.FolFormula>, net.sf.tweety.commons.Reasoner<Boolean,RclBeliefSet,net.sf.tweety.logics.fol.syntax.FolFormula>

public class SimpleRelationalCReasoner
extends Object
implements net.sf.tweety.commons.QualitativeReasoner<RclBeliefSet,net.sf.tweety.logics.fol.syntax.FolFormula>, net.sf.tweety.commons.ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>

This class models a relational brute force c-reasoner for relational conditional logic. Reasoning is performed by computing a minimal c-representation for the given knowledge base.
A c-representation for a conditional knowledge base R={r1,...,rn} is a ranking function k such that k accepts every conditional in R (k |= R) and if there are numbers k0,k1+,k1-,...,kn+,kn- with
k(w)=k0 + \sum_{w verifies ri} ki+ + \sum_{w falsifies ri} kj- for every w. A c-representation is minimal if k0+...+kn- is minimal.
The c-representation is computed using a brute force approach.

See Gabriele Kern-Isberner. Conditionals in nonmonotonic reasoning and belief revision. Lecture Notes in Computer Science, Volume 2087. 2001.

See also [Kern-Isberner,Thimm, "A Ranking Semantics for Relational Defaults", in preparation].

Author:

Matthias Thimm

Constructor Summary

Constructors

Constructor and Description
SimpleRelationalCReasoner(boolean simple) Creates a new relational c-representation reasoner.

Method Summary

Modifier and Type	Method and Description
RelationalRankingFunction	getModel(RclBeliefSet bbase)
RelationalRankingFunction	getModel(RclBeliefSet bs, net.sf.tweety.logics.fol.syntax.FolSignature signature) Retrieves the C representation of the given belief set wrt.
Collection<RelationalRankingFunction>	getModels(RclBeliefSet bbase)
Boolean	query(RclBeliefSet bs, net.sf.tweety.logics.fol.syntax.FolFormula query)
Boolean	query(RclBeliefSet bs, net.sf.tweety.logics.fol.syntax.FolFormula query, net.sf.tweety.logics.fol.syntax.FolSignature signature) Queries the given belief set wrt.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleRelationalCReasoner

public SimpleRelationalCReasoner(boolean simple)

Creates a new relational c-representation reasoner.

Parameters:

simple - whether the computed c-representation is simple.

Method Detail

query

public Boolean query(RclBeliefSet bs,
                     net.sf.tweety.logics.fol.syntax.FolFormula query,
                     net.sf.tweety.logics.fol.syntax.FolSignature signature)

Queries the given belief set wrt. the given signature.

Parameters:

bs - some belief set

query - some query

signature - some signature

Returns:

query

public Boolean query(RclBeliefSet bs,
                     net.sf.tweety.logics.fol.syntax.FolFormula query)

Specified by:

query in interface net.sf.tweety.commons.QualitativeReasoner<RclBeliefSet,net.sf.tweety.logics.fol.syntax.FolFormula>

Specified by:

query in interface net.sf.tweety.commons.Reasoner<Boolean,RclBeliefSet,net.sf.tweety.logics.fol.syntax.FolFormula>

getModels

public Collection<RelationalRankingFunction> getModels(RclBeliefSet bbase)

Specified by:

getModels in interface net.sf.tweety.commons.ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>

getModel

public RelationalRankingFunction getModel(RclBeliefSet bbase)

Specified by:

getModel in interface net.sf.tweety.commons.ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>

getModel

public RelationalRankingFunction getModel(RclBeliefSet bs,
                                          net.sf.tweety.logics.fol.syntax.FolSignature signature)

Retrieves the C representation of the given belief set wrt. the given signature

Parameters:

bs - some belief set

signature - some signature

Returns:

the c representation (a ranking function)