Completeness Guaranteed Approximations for OWL-DL Query Answering.

Abstract

How to provide scalable and quality guaranteed approximation for query answering over expressive description logics (DLs) is an important problem in knowledge representation (KR). This is a pressing issue, in particular due to the fact that, for the widely used standard Web Ontology Language OWL, whether conjunctive query answering is decidable is still an open problem. Pan and Thomas propose a soundness guaranteed approximation, which transforms an ontology in a more expressive DL to its least upper bound approximation in a tractable DL. In this paper, we investigate a completeness guaranteed approximation, based on transformations of both the source ontology and input queries. We have implemented both soundness guaranteed and completeness guaranteed approximations in our TrOWL ontology reasoning infrastructure.