Package org.tweetyproject.logics.rcl.reasoner

Class SimpleRelationalCReasoner

java.lang.Object

org.tweetyproject.logics.rcl.reasoner.SimpleRelationalCReasoner

All Implemented Interfaces:

ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>, QualitativeReasoner<RclBeliefSet,FolFormula>, Reasoner<Boolean,RclBeliefSet,FolFormula>

public class SimpleRelationalCReasoner
extends Object
implements QualitativeReasoner<RclBeliefSet,FolFormula>, 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	Description
SimpleRelationalCReasoner(boolean simple)	Creates a new relational c-representation reasoner.

Method Summary

Modifier and Type	Method	Description
RelationalRankingFunction	getModel(RclBeliefSet bbase)	Returns a single (dedicated) model of the given belief base.
RelationalRankingFunction	getModel(RclBeliefSet bs, FolSignature signature)	Retrieves the C representation of the given belief set wrt.
Collection<RelationalRankingFunction>	getModels(RclBeliefSet bbase)	Returns a characterizing model of the given belief base
boolean	isInstalled()	Checks whether the underlying solver or reasoning mechanism used by this reasoner is installed and available for use.
Boolean	query(RclBeliefSet bs, FolFormula query)	Queries the given belief base with the provided formula and returns a boolean result.
Boolean	query(RclBeliefSet bs, FolFormula query, FolSignature signature)	Queries the given belief set wrt.

Methods inherited from class java.lang.Object

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

Constructor Details

SimpleRelationalCReasoner

public SimpleRelationalCReasoner(boolean simple)

Creates a new relational c-representation reasoner.

Parameters:

simple - whether the computed c-representation is simple.

Method Details

query

public Boolean query(RclBeliefSet bs,
 FolFormula query,
 FolSignature signature)

Queries the given belief set wrt. the given signature.

Parameters:

bs - some belief set

query - some query

signature - some signature

Returns:

true iff the query is true

query

public Boolean query(RclBeliefSet bs,
 FolFormula query)

Description copied from interface: QualitativeReasoner

Queries the given belief base with the provided formula and returns a boolean result. The result indicates whether the formula is entailed or satisfied by the belief base according to the qualitative reasoning method implemented by the reasoner.

Specified by:

query in interface QualitativeReasoner<RclBeliefSet,FolFormula>

Specified by:

query in interface Reasoner<Boolean,RclBeliefSet,FolFormula>

Parameters:

bs - The belief base to be queried.

query - The formula for which the query is made.

Returns:

`TRUE` if the formula is entailed or satisfied by the belief base, `FALSE` otherwise.

getModels

public Collection<RelationalRankingFunction> getModels(RclBeliefSet bbase)

Description copied from interface: ModelProvider

Returns a characterizing model of the given belief base

Specified by:

getModels in interface ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>

Parameters:

bbase - some belief base

Returns:

the (selected) models of the belief base

getModel

public RelationalRankingFunction getModel(RclBeliefSet bbase)

Description copied from interface: ModelProvider

Returns a single (dedicated) model of the given belief base. If the implemented method allows for more than one dedicated model, the selection may be non-deterministic.

Specified by:

getModel in interface ModelProvider<RelationalConditional,RclBeliefSet,RelationalRankingFunction>

Parameters:

bbase - some belief base

Returns:

a selected model of the belief base.

getModel

public RelationalRankingFunction getModel(RclBeliefSet bs,
 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)

isInstalled

public boolean isInstalled()

Description copied from interface: QualitativeReasoner

Checks whether the underlying solver or reasoning mechanism used by this reasoner is installed and available for use. This can be helpful when the reasoner depends on external tools or libraries for performing the reasoning tasks.

Specified by:

isInstalled in interface QualitativeReasoner<RclBeliefSet,FolFormula>

Returns:

`true` if the solver is installed and available, `false` otherwise.