Queries to Hybrid MKNF Knowledge Bases through Oracular Tabling

An important issue for the Semantic Web is how to combine open-world ontology languages with closed-world (non-monotonic) rule paradigms. Several proposals for hybrid languages allow concepts to be simultaneously defined by an ontology and rules, where rules may refer to concepts in the ontology and the ontology may also refer to predicates defined by the rules. Hybrid MKNF knowledge bases are one such proposal, for which both a stable and a well-founded semantics have been defined. The definition of Hybrid MKNF knowledge bases is parametric on the ontology language, in the sense that non-monotonic rules can extend any decidable ontology language. In this paper we define a query-driven procedure for Hybrid MKNF knowledge bases that is sound with respect to the original stable model-based semantics, and is correct with respect to the well-founded semantics. This procedure is able to answer conjunctive queries, and is parametric on an inference engine for reasoning in the ontology l...

• Type: Conference
• Year: 2009
• Where: SEMWEB
• Authors: José Júlio Alferes, Matthias Knorr, Terrance Swift
• Keywords: Hybrid Mknf Knowledge, Internet Technology, Ontology, Ontology Language, SEMWEB 2009