A Definition of Sceptical Semantics in the Constellations Approach

Stefano Bistarelli, Francesco Santini

Abstract: We propose a different way to compute sceptical semantics in the constellations approach: we define the grounded, ideal, and eager extension of a Probabilistic Argumentation Framework by merging the subsets with the maximal probability of complete, preferred, semi-stable extensions respectively. Differently from the original work (i.e., [19]), the extension we propose is unique, as the principle of scepticism usually demands. This definition maintains some well-known properties, as set-inclusion among the three semantics. Moreover, we advance a quantitative relaxation of these semantics with the purpose to mitigate scepticism in case the result corresponds to empty-set, which is not very informative.