Declutter Your Justifications: Determining Similarity Between OWL Explanations
Samantha Bail, Bijan Parsia, Ulrike Sattler · Research Explorer (The University of Manchester) · 2012
Given the high expressivity of the Web Ontology Language OWL 2, there is a potential for great diversity in the logical content of OWL ontologies. The fact that many naturally occurring entailments of such ontologies have multiple justifications indicates that ontologies often overdetermine their consequences, suggesting a diversity in supporting reasons. On closer inspection, however, we often find that justifications – even for multiple entailments – appear to be structurally similar, suggesting that their multiplicity might be due to diverse material, not formal grounds for an entailment. In this paper, we introduce and explore several equivalence relations over justifications for entailments of OWL ontologies which partition a set of justifications into structurally similar subsets. These equivalence relations range from strict isomorphism to looser notions of similarity, covering justifications which contain different class expressions, or even different numbers of axioms. We present the results of a survey of 83 ontologies from the bio-medical domain, showing that OWL ontologies used in practice often contain large numbers of structurally similar justifications.