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W. Dvorak, A. Rapberger, S. Woltran:
"Argumentation Semantics under a Claim-centric View: Properties, Expressiveness and Relation to SETAFs";
Talk: KR 2020 - 17th International Conference on Principles of Knowledge Representation and Reasoning, Rhodos, Griechenland; 2020-09-12 - 2020-09-18; in: "Proceedings of the 17th International Conference on Principles of Knowledge Representation and Reasoning, {KR} 2020, Rhodes, Greece, September 12-18, 2020", (2020), 341 - 350.

Claim-augmented argumentation frameworks (CAFs) constitute
a generic formalism for conflict resolution of conclusionoriented
problems in argumentation. CAFs extend Dung argumentation
frameworks (AFs) by assigning a claim to each
argument. So far, semantics for CAFs are defined with respect
to the underlying AF by interpreting the extensions of
the respective AF semantics in terms of the claims of the
accepted arguments; we refer to them as inherited semantics
of CAFs. A central concept of many argumentation semantics
is maximization, which can be done with respect to
arguments as in preferred semantics, or with respect to the
range as in semi-stable semantics. However, common instantiations
of argumentation frameworks require maximality
on the claim-level and inherited semantics often fail to provide
maximal claim-sets even if the underlying AF semantics
yields maximal argument sets. To address this issue, we investigate
a different approach and introduce claim-level semantics
(cl-semantics) for CAFs where maximization is performed
on the claim-level. We compare these two approaches
for five prominent semantics (preferred, naive, stable, semistable,
and stage) and relate in total eleven CAF semantics
to each other. Moreover, we show that for a certain subclass
of CAFs, namely well-formed CAFs, the different versions
of preferred and stable semantics coincide, which is not the
case for the remaining semantics. We furthermore investigate
a recently established translation between well-formed CAFs
and SETAFs and show that, in contrast to the inherited naive,
semi-stable and stage semantics, the cl-semantics correspond
to the respective SETAF semantics. Finally, we investigate
the expressiveness of the considered semantics in terms of
their signatures.

http://dx.doi.org/10.24963/kr.2020/35

Project Head Stefan Szeider:
DK - Logic

Project Head Johannes Peter Wallner:
EMBArg