The Effect of Preferences in Abstract Argumentation under a Claim-Centric View

In this paper, we study the effect of preferences in abstract argumentation under a claim-centric perspective. Recent work has revealed that semantical and computational properties can change when reasoning is performed on claim-level rather than on the argument-level, while under certain natural restrictions (arguments with the same claims have the same outgoing attacks) these properties are conserved. We now investigate these effects when, in addition, preferences have to be taken into account and consider four prominent reductions to handle preferences between arguments. As we shall see, these reductions give rise to four new classes of claim-augmented argumentation frameworks. These classes behave differently from each other with respect to semantic properties and computational complexity, but also in connection with structured argumentation formalisms such as assumption-based argumentation. This strengthens the view that the actual choice for handling preferences has to be taken with care.