Relevant Closure: A New Form of Defeasible Reasoning for Description Logics

Giovanni Casini, Thomas Meyer, Kody Moodley, Riku Nortjé

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingAcademicpeer-review


Among the various proposals for defeasible reasoning for description logics, rational closure, a procedure originally defined for propositional logic, turns out to have a number of desirable properties. Not only it is computationally feasible, but it can also be implemented using existing classical reasoners. One of its drawbacks is that it can be seen as too weak from the inferential point of view. To overcome this limitation we introduce in this paper two extensions of rational closure: basic relevant closure and minimal relevant closure. As the names suggest, both rely on defining a version of relevance. Our formalisation of relevance in this context is based on the notion of a justification (a minimal subset of sentences implying a given sentence). This is, to our knowledge, the first proposal for defining defeasibility in terms of justifications—a notion that is well-established in the area of ontology debugging. Both basic and minimal relevant closure increase the inferential power of rational closure, giving back intuitive conclusions that cannot be obtained from rational closure. We analyse the properties and present algorithms for both basic and minimal relevant closure, and provide experimental results for both basic relevant closure and minimal relevant closure, comparing it with rational closure.
Original languageEnglish
Title of host publicationLogics in Artificial Intelligence
Subtitle of host publication14th European Conference, JELIA 2014, Funchal, Madeira, Portugal, September 24-26, 2014. Proceedings
EditorsEduardo Fermé, João Leite
Number of pages15
ISBN (Electronic)9783319115580
ISBN (Print)9783319115573
Publication statusPublished - 2014
Externally publishedYes

Publication series

SeriesLecture Notes in Computer Science

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