Tech Reports


Uncontested Semantics for Value-Based Argumentation

Paul E. Dunne


We introduce an extension-based semantics for value-based argumentation frameworks (VAFs) that provides a counterpart to the recently proposed ideal semantics in standard - i.e. value-free - argumentation frameworks. A significant motivation for this so-called 'uncontested semantics' is as a mechanism with which to refine the nature of objective acceptance: thus the set of uncontested arguments are not only considered justified irrespective of the value ordering endorsed by any audience but, in addition, collectively constitute a self-defending and internally consistent collection of beliefs within the framework. In this way the rationale underpinning objectively accepted arguments which fall outside this uncontested set must involve audience related features. In this paper we formalise the concept of uncontested arguments in VAFs, present a number of features distinguishing ideal and uncontested semantics, and analyse some basic complexity-theoretic issues.

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