Versioning Based on Logical Difference for Lightweight Description Logic Terminologies

We study a logic-based approach to versioning of ontologies. Under this view, ontologies provide answers to queries about some vocabulary of interest. The difference between two versions of an ontology is given by the set of queries that receive different answers. We investigate this approach for terminologies given in the description logic EL extended with role inclusions and range restrictions for three distinct types of queries: subsumption, instance, and conjunctive queries. We present an implementation, CEX2, that computes finite representations of the respective difference between terminologies.