Flexible intensional query-answering for RDF peer-to-peer systems

Abstract

We consider the Peer-To-Peer (P2P) database systems with RDF ontologies and with the semantic characterization of P2P mappings based on logical views over local peer's ontology. Such kind of virtual-predicate based mappings needs an embedding of RDF ontologies into a predicate first-order logic, or at some of its sublanguages as, for example, logic programs for deductive databases. We consider a peer as a local epistemic logic system with its own belief based on RDF tuples, independent from other peers and their own beliefs. This motivates the need of a semantic characterization of P2P mappings based not on the extension but on the meaning of concepts used in the mappings, that is, based on intensional logic. We show that it adequately models robust weakly-coupled framework of RDF ontologies and supports decidable query answering for the union of conjunctive queries. © Springer-Verlag Berlin Heidelberg 2006.