Import-by-query: ontology reasoning under access limitations

To enable ontology reuse, the Web Ontology Language (OWL) allows an ontology κv to import an ontology κh. To reason with such a κv, a reasoner needs physical access to the axioms of κh. For copyright and/or privacy reasons, however, the authors of κh might not want to publish the axioms of κh; instead, they might prefer to provide an oracle that can answer a (limited) set of queries over κh, thus allowing κv to import κh "by query." In this paper, we study import-by-query algorithms, which can answer questions about κv ∪ κh by accessing only κv and the oracle. We show that no such algorithm exists in general, and present restrictions under which importing by query becomes feasible.