Extension-ranking Semantics for Abstract Argumentation Preprint

In this paper, we present a general framework for ranking sets of arguments in abstract argumentation based on their plausibility of acceptance. We present a generalisation of Dung's extension semantics as extension-ranking semantics, which induce a preorder over the power set of all arguments, allow ing us to state that one set is "closer" to being acceptable than another . To evaluate the extension-ranking semantics, we introduce a number of p rinciples that a well-behaved extension-ranking semantics should satisfy. W e consider several simple base relations, each of which models a single central a spect of argumentative reasoning. The combination of these base relations provides us with a family of extension-ranking semantics. We also adapt a numb er of approaches from the literature for ranking extensions to be us able in the context of extension-ranking semantics, and evaluate their beha viour. Keywords: Abstract Argumentation, Ranking Sets of Objects, Extension-ranking semantics 1. Introduction Formal argumentation [7] is concerned with models of rational decis ion-making based on representations of arguments and their relations.