An Authority Degree-Based Evaluation Strategy for Abstract Argumentation Frameworks

Abstract argumentation allows to determine in an easy, formal way which claims survive in a conflicting dispute. It works by considering claims as abstract entities, and expressing attack relationships among them. However, this level of expressiveness prevents abstract argumentation systems from being directly applied to reasoning processes where the context is relevant. An outstanding example is when a claim is supported by appealing to authority, so that the audience assigns reliability to the claim's justication based on the authority's renowned experience in the domain. To handle this, we propose to enrich the classical representation used in abstract argumentation by associating arguments with weights that express their degree of authority. The weights' values define their strength in the given domain, which in turn should affect the evaluation of their degree of justification. This paper defines a strategy to combine these weights in order to determine which arguments withstand in a dispute concerning a given domain. Such a strategy was implemented in the ARCA system, that allows to comfortably set up argumentation problems and solve them using both traditional extension-based semantics and the proposed evaluation approach. ARCA is used to illustrate the proposed strategy by means of sample use cases.