Complexity-Sensitive Decision Procedures for Abstract Argumentation

Lecturer : 
Matti Järvisalo
Event type: 
HIIT seminar
Event time: 
2012-03-09 10:15 to 11:15
Place: 
Kumpula Exactum C222
Description: 


Abstract argumentation frameworks (AFs) provide the basis for various
reasoning problems in the areas of Knowledge Representation and Artificial
Intelligence. Efficient evaluation of AFs has thus been identified as an
important research challenge. So far, implemented systems for evaluating
AFs have either followed a straight-forward reduction-based approach or
been limited to certain tractable classes of AFs. In this work, we present
a generic approach for reasoning over AFs, based on the novel concept of
complexity-sensitivity. Establishing the theoretical foundations of this
approach, we derive several new complexity results for preferred,
semi-stable and stage semantics which complement the current complexity
landscape for abstract argumentation, providing further understanding on
the sources of intractability of AF reasoning problems. The introduced
generic framework exploits decision procedures for problems of lower
complexity whenever possible. This allows, in particular, instantiations of
the generic framework via harnessing in an iterative way current
sophisticated Boolean satisfiability (SAT) solver technology for solving
the considered AF reasoning problems. First experimental results show that
the SAT-based instantiation of our novel approach outperforms existing
systems.

Joint work with Wolfgang Dvorak, Johannes Peter Wallner, and Stefan Woltran
(TU Vienna).

Paper to appear in Proceedings of the 13th International Conference on 
Principles of Knowledge Representation and Reasoning (KR 2012).
 


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