| Abstract |
In this paper we present a framework for answering queries over inconsistent ontologies by using contrastive reasoning, the reasoning of contrasts which are expressed as contrary conjunctions like the word ``but'' in natural language. We argue that contrastive answers are more informative for reasoning with inconsistent ontologies, as compared with the usual simple boolean answer, i.e., either ``yes'' or ``no''. We propose a general approach to obtaining contrastive answers from inconsistent ontologies, including an algorithm for computing contrastive answers. The proposed framework has been implemented in the system CRION (Contrastive Reasoning with Inconsistent ONtologies) as a reasoning plug-in in the LarKC (Large Knowledge Collider) platform. We report several experiments in which we apply the CRION system to some realistic ontologies. This evaluation shows that contrastive reasoning is a useful extension to the existing approaches of reasoning with inconsistent ontologies. |