A KLM Perspective on Defeasible Reasoning for Description Logics

Britz, Katarina and Casini, Giovanni and Meyer, Thomas and Varzinczak, Ivan (2019) A KLM Perspective on Defeasible Reasoning for Description Logics, Description Logic, Theory Combination, and All ThatC, LNCS, 11560, Springer.

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In this paper we present an approach to defeasible reasoning for the description logic ALC. The results discussed here are based on work done by Kraus, Lehmann and Magidor (KLM) on defeasible conditionals in the propositional case. We consider versions of a preferential semantics for two forms of defeasible subsumption, and link these semantic constructions formally to KLM-style syntactic properties via representation results. In addition to showing that the semantics is appropriate, these results pave the way for more effective decision procedures for defeasible reasoning in description logics. With the semantics of the defeasible version of ALC in place, we turn to the investigation of an appropriate form of defeasible entailment for this enriched version of ALC. This investigation includes an algorithm for the computation of a form of defeasible entailment known as rational closure in the propositional case. Importantly, the algorithm relies completely on classical entailment checks and shows that the computational complexity of reasoning over defeasible ontologies is no worse than that of the underlying classical ALC. Before concluding, we take a brief tour of some existing work on defeasible extensions of ALC that go beyond defeasible subsumption.

Item Type: Book chapter
Subjects: Computing methodologies > Artificial intelligence
Date Deposited: 15 Jan 2020 11:26
Last Modified: 15 Jan 2020 11:26
URI: http://pubs.cs.uct.ac.za/id/eprint/1363

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