Query answering over contextualized RDF/OWL knowledge with forall-existential bridge rules: Decidable finite extension classes

The proliferation of contextualized knowledge in the Semantic Web (SW) has led to the popularity of knowledge formats such as quads in the SW community. A quad is an extension of RDF triple with the contextual information of the triple. We in this paper, study the problem of query answering over quads augmented with forall-existential bridge rules that enable interoperability of reasoning between the triples in various contexts. We call a set of quads together with such expressive bridge rules, a quad-system. Query answering over quad-systems is undecidable, in general. We derive decidable classes of quad-systems, for which query answering can be done using forward chaining. Sound, complete and terminating procedures, which are adaptations of the well known chase algorithm, are provided for these classes for deciding query entailment. Safe, msafe, and csafe class of quad-systems restrict the structure of blank nodes generated during the chase computation process to be directed acyclic ...

• Type: Journal
• Year: 2016
• Where: SEMWEB
• Authors: Mathew Joseph, Gabriel M. Kuper, Till Mossakowski, Luciano Serafini
• Keywords: Internet Technology, SEMWEB 2016