  Abstract argumentation framework (\AFname) is a unifying framework able to
encompass a variety of nonmonotonic reasoning approaches, logic programming and
computational argumentation. Yet, efficient approaches for most of the decision
and enumeration problems associated to \AFname s are missing, thus potentially
limiting the efficacy of argumentation-based approaches in real domains. In
this paper, we present an algorithm for enumerating the preferred extensions of
abstract argumentation frameworks which exploits parallel computation. To this
purpose, the SCC-recursive semantics definition schema is adopted, where
extensions are defined at the level of specific sub-frameworks. The algorithm
shows significant performance improvements in large frameworks, in terms of
number of solutions found and speedup.
