In the context of Dung's theory of argumentation frameworks, comparisons between argumentation semantics are often focused on the different behavior they show in some (more or less peculiar) cases. It is also interesting however to characterize situations where (under some reasonably general assumptions) different semantics behave exactly in the same way. Focusing on the general family of SCC-recursive argumentation semantics, the paper provides some novel results in this line. In particular, we study the characterization of defeat graphs where any SCC-recursive semantics admits exactly one extension coinciding with the grounded extension. Then, we consider the problem of agreement with stable semantics and identify the family of SCC-symmetric argumentation frameworks, where agreement is ensured for a class of multiple-status argumentation semantics including stable, preferred and CF2 semantics.
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