TY - JOUR AU - Baumann, Ringo AU - Brewka, Gerhard PY - 2019/07/17 Y2 - 2024/03/29 TI - Extension Removal in Abstract Argumentation – An Axiomatic Approach JF - Proceedings of the AAAI Conference on Artificial Intelligence JA - AAAI VL - 33 IS - 01 SE - AAAI Technical Track: Knowledge Representation and Reasoning DO - 10.1609/aaai.v33i01.33012670 UR - https://ojs.aaai.org/index.php/AAAI/article/view/4116 SP - 2670-2677 AB - <p>This paper continues the rather recent line of research on the dynamics of non-monotonic formalisms. In particular, we consider semantic changes in Dung’s abstract argumentation formalism. One of the most studied problems in this context is the so-called <em>enforcing problem</em> which is concerned with manipulating argumentation frameworks (AFs) such that a certain desired set of arguments becomes an extension. Here we study the inverse problem, namely the <em>extension removal problem</em>: is it possible – and if so how – to modify a given argumentation framework in such a way that certain undesired extensions are no longer generated? Analogously to the well known AGM paradigm we develop an axiomatic approach to the removal problem, i.e. a certain set of axioms will determine suitable manipulations. Although contraction (that is, the elimination of a particular belief) is conceptually quite different from extension removal, there are surprisingly deep connections between the two: it turns out that postulates for removal can be directly obtained as reformulations of the AGM contraction postulates. We prove a series of formal results including conditional and unconditional existence and semantical uniqueness of removal operators as well as various impossibility results – and show possible ways out.</p> ER -