The Logical Difference for the Lightweight Description Logic EL
This work addresses versioning issues for ontologies in fields like bioinformatics, but it is incremental as it builds on existing logic-based approaches.
The paper tackles the problem of computing differences between ontology versions by defining the logical difference as the set of queries with different answers, and presents polynomial-time algorithms for three query types in the EL description logic, with an implementation applied to Snomed CT and NCI ontology versions.
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 domain and range restrictions for three distinct types of queries: subsumption, instance, and conjunctive queries. In all three cases, we present polynomial-time algorithms that decide whether two terminologies give the same answers to queries over a given vocabulary and compute a succinct representation of the difference if it is non- empty. We present an implementation, CEX2, of the developed algorithms for subsumption and instance queries and apply it to distinct versions of Snomed CT and the NCI ontology.