© 2004 by Oxford University Press
Original Article |
Argumentation Semantics for Defeasible Logic
1 School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia. E-mail: guido{at}itee.uq.edu.au 2 National ICT Australia, C/o School of Computer Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia. E-mail: mmaher{at}cse.unsw.ed.au 3 Institute of Computer Science, FORTH, PO Box 1385, 71110 Heraklion, Crete, Greece. E-mail: antoniou{at}ics.forth.edu 4 School of Computing and Information Technology, Griffith University, Nathan, QLD 4111, Australia. E-mail: d.billington{at}griffith.edu.au
Defeasible reasoning is a simple but efficient rule-based approach to nonmonotonic reasoning. It has powerful implementations and shows promise to be applied in the areas of legal reasoning and the modelling of business rules. This paper establishes significant links between defeasible reasoning and argumentation. In particular, Dung-like argumentation semantics is provided for two key defeasible logics, of which one is ambiguity propagating and the other ambiguity blocking. There are several reasons for the significance of this work: (a) establishing links between formal systems leads to a better understanding and cross-fertilization, in particular our work sheds light on the argumentation-theoretic features of defeasible logic; (b) we provide the first ambiguity blocking Dung-like argumentation system; (c) defeasible reasoning may provide an efficient implementation platform for systems of argumentation; and (d) argumentation-based semantics support a deeper understanding of defeasible reasoning, especially in the context of the intended applications.
Keywords: Defeasiblre logic, argumentation semantics, nonmonotonic reasoning
Received 9 December 2002.