net.sf.tweety.arg.lp

Class ArgumentationReasoner

java.lang.Object

net.sf.tweety.commons.Reasoner

net.sf.tweety.arg.lp.ArgumentationReasoner

Direct Known Subclasses:

LiteralReasoner

public class ArgumentationReasoner
extends net.sf.tweety.commons.Reasoner

This class models a reasoner for extended logic programming based arguments using the fixpoint semantics from [1] parameterised by a notion of attack x for the opponent and another notion of attack y as a defense for the proponent. This base implementation only allows to query whether an argument A is x/y-justified in a ELP P. A is called x/y-acceptable wrt. a set of arguments S if for every argument B in P such that (B,A) \in x there exists an argument C \in S such that (C,B) \in y. The set of acceptable arguments for P is defined as the fixpoint J_{P,x/y} of the function F_{P,x/y}(S) = { A | A is x/y-acceptable with regard to S} In [1] it is shown that J_{a/u} equals Dung's grounded semantics, J_{u/su} equals the well founded semantics for normal logic programs and J_{u/a} equals the well-founded semantics for logic programs with explicit negation. [1] Ralf Schweimeier and Michael Schroeder: A Parameterised Hierarchy of Argumentation Semantics for Extended Logic Programming and its Application to the Well-founded Semantics. In: Theory and Practice of Logic Programming, 5(1-2):207-242, 2003.

Author:

Sebastian Homann

Constructor Summary

Constructors

Constructor and Description
ArgumentationReasoner(net.sf.tweety.commons.BeliefBase beliefBase, AttackStrategy attack, AttackStrategy defence) Creates a new ArgumentationReasoner for the given belief base and parameterised by a notion of attack for the opponent and another notion of attack for the defense

Method Summary

Modifier and Type	Method and Description
Set<Argument>	getDefensibleArguments() Returns the set of defensible arguments, i.e.
Set<Argument>	getJustifiedArguments() Returns the set of x/y-justified arguments using a bottom-up fixpoint calculation
Set<Argument>	getOverruledArguments() Returns the set of overruled arguments, i.e.
boolean	isDefensible(Argument arg) An argument is called x/y-defensible if it is neither x/y-justified nor x/y-overruled.
boolean	isJustified(Argument arg) An argument is called x/y-justified if it is contained in J_{P,x/y}.
boolean	isOverruled(Argument arg) An argument is called x/y-overruled, if it is attacked by an x/y-justified argument.
net.sf.tweety.commons.Answer	query(net.sf.tweety.commons.Formula query)

Methods inherited from class net.sf.tweety.commons.Reasoner

getKnowledgeBase

Methods inherited from class java.lang.Object

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

Constructor Detail

ArgumentationReasoner

public ArgumentationReasoner(net.sf.tweety.commons.BeliefBase beliefBase,
                             AttackStrategy attack,
                             AttackStrategy defence)

Creates a new ArgumentationReasoner for the given belief base and parameterised by a notion of attack for the opponent and another notion of attack for the defense

Parameters:

beliefBase -

attack -

defence -

Method Detail

query

public net.sf.tweety.commons.Answer query(net.sf.tweety.commons.Formula query)

Specified by:

query in class net.sf.tweety.commons.Reasoner

isOverruled

public boolean isOverruled(Argument arg)

An argument is called x/y-overruled, if it is attacked by an x/y-justified argument.

Parameters:

arg - an argument

Returns:

true iff arg is x-attacked by an x/y-justified argument

isJustified

public boolean isJustified(Argument arg)

An argument is called x/y-justified if it is contained in J_{P,x/y}. See class description for details.

Parameters:

arg - an argument

Returns:

true iff arg is x/y-justified

isDefensible

public boolean isDefensible(Argument arg)

An argument is called x/y-defensible if it is neither x/y-justified nor x/y-overruled.

Parameters:

arg - an argument

Returns:

true iff arg is neither x/y-justified nor x/y-overruled.

getJustifiedArguments

public Set<Argument> getJustifiedArguments()

Returns the set of x/y-justified arguments using a bottom-up fixpoint calculation

Returns:

the set of x/y-justified arguments

getOverruledArguments

public Set<Argument> getOverruledArguments()

Returns the set of overruled arguments, i.e. the set of arguments, which are attacked by a justified argument.

Returns:

the set of overruled arguments.

getDefensibleArguments

public Set<Argument> getDefensibleArguments()

Returns the set of defensible arguments, i.e. the set of arguments, that are neither justified nor overruled.

Returns:

the set of defensible arguments.