Approximating Operators and Semantics for Abstract Dialectical Frameworks

We provide a systematic in-depth study of the semantics of abstract dialectical frameworks (ADFs), a recent generalisation of Dung\'s abstract argumentation frameworks. This is done by associating with an ADF its characteristic one-step consequence operator and defining various semantics for AD...

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Bibliographic Details
Main Author: Strass, Hannes
Other Authors: Universität Leipzig, Fakultät für Mathematik und Informatik
Format: Others
Language:English
Published: Universitätsbibliothek Leipzig 2013
Subjects:
Online Access:http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-102943
http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-102943
http://www.qucosa.de/fileadmin/data/qucosa/documents/10294/report1.pdf
Description
Summary:We provide a systematic in-depth study of the semantics of abstract dialectical frameworks (ADFs), a recent generalisation of Dung\'s abstract argumentation frameworks. This is done by associating with an ADF its characteristic one-step consequence operator and defining various semantics for ADFs as different fixpoints of this operator. We first show that several existing semantical notions are faithfully captured by our definition, then proceed to define new ADF semantics and show that they are proper generalisations of existing argumentation semantics from the literature. Most remarkably, this operator-based approach allows us to compare ADFs to related nonmonotonic formalisms like Dung argumentation frameworks and propositional logic programs. We use polynomial, faithful and modular translations to relate the formalisms, and our results show that both abstract argumentation frameworks and abstract dialectical frameworks are at most as expressive as propositional normal logic programs.