An SCC Recursive Meta-Algorithm for Computing Preferred Labellings in Abstract Argumentation

ABSTRACT. This paper presents a meta-algorithm, based on the general recursive schema for argumentation semantics called SCC-Recursiveness, for the computation of preferred labellings. The idea is to recursively decompose a framework so as to compute semantics labellings on restricted sub-frameworks, in order to reduce the computational effort. The meta-algorithm can be instantiated with a specific "base algorithm", applied to the base case of the recursion, which can be obtained by generalizing existing algorithms in order to compute labellings in restricted sub-frameworks. We devise to this purpose a generalization of a SAT-based state-of-the art algorithm, and provide an empirical investigation to show the significant improvement of performances obtained by exploiting the SCC-recursive schema.