Lecture Notes in Computer Science Volume 5926, 2009, pp 306-320

A Relevance-Directed Algorithm for Finding Justifications of DL Entailments

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Finding the justifications of an entailment, i.e. minimal sets of axioms responsible for the entailment, is an important problem in ontology engineering and thus has become a key reasoning task for Description Logic-based ontologies. Although practical techniques to find all possible justifications exist, efficiency is still a problem. Furthermore, in the worst case the number of justifications for a subsumption entailment is exponential in the size of the ontology. Therefore, it is not always desirable to compute all justifications. In this paper, we propose a novel black-box algorithm that iteratively constructs a set of justifications of an entailment using a relevance-based selection function. Each justification returned by our algorithm is attached with a weight denoting its relevance degree w.r.t. the entailment. Finally, we implement the algorithm and present evaluation results over real-life ontologies that show the benefits of the selection function.