Аспирантский семинар: Data Complexity of Answering Ontology-Mediated Queries with a Covering Axiom

Where: Faculty of Computer Science, Kochnovskii proezd, 3, room 509.
When: 18:10 – 19:30 on November 19.
Speaker: Olga Gerasimova

We work with an application of specific ontologies to facilitate access to various types of data sources that is known as ontology-based data access (OBDA) where an ontology is used to support query answering for distributed and heterogeneous data sources. For this approach to work, one has to carefully choose the ontology language. We considered ontologies formulated in terms of a suitable description logic. The OWL 2 Web Ontology Language is an ontology language for the Semantic Web recently designed ad standardised by the W3C. We use the OWL 2 QL profile designed specifically for OBDA via query rewriting. Unfortunately, OWL 2 QL does not contain many concept and role constructs that are useful in many OBDA applications such as disjunction (or union) on the right-hand side of concept inclusions. In order to apply OBDA to the data with a complex structure, we could adapt first-order (FO) rewritability to the concrete query and ontology required by a user.