Coalitional Games for Abstract Argumentation Coalitional Games for Abstract Argumentation 1

In this work we address the issue of the uncertainty faced by a user participating in multiagent debate. We propose a way to compute the relative relevance of arguments for such a user, by merging the classical argumentation framework proposed in [5] into a game theoretic coalitional setting, where the worth of a collection of arguments (opinions) can be seen as the combination of the information concerning the defeat relation and the preferences over arguments of a “user”. Via a property-driven approach, we show that the Shapley value [15] for coalitional games defined over an argumentation framework, can be applied to resume all the information about the worth of opinions into an attribution of relevance for the single arguments. We also prove that, for a large family of (coalitional) argumentation frameworks, the Shapley value can be easily computed.