Extending the RDFS entailment Lemma

Abstract

We complement the RDF semantics specification of the W3C by proving decidability of RDFS entailment. Furthermore, we show completeness and decidability of entailment for RDFS extended with datatypes and a property-related subset of OWL. The RDF semantics specification provides a complete set of entailment rules for reasoning with RDFS, but does not prove decidability of RDFS entailment: the closure graphs used in the completeness proof are infinite for finite RDF graphs. We define partial closure graphs, which can be taken to be finite for finite RDF graphs, which can be computed in polynomial time, and which are sufficient to decide RDFS entailment. We consider the extension of RDFS with datatypes and a propertyrelated fragment of OWL: FunctionalProperty, InverseFunctionalProperty, sameAs, SymmetricProperty, TransitiveProperty, and inversedf. In order to obtain a complete set of simple entailment rules, the semantics that we use for these extensions is in line with the 'ifsemantics' of RDFS, and weaker than the 'iff-semantics' defining Dentailment and OWL (DL or Full) entailment. Classes can be used as instances, the use of FunctionalProperty and TransitiveProperty is not restricted to obtain decidability, and a partial closure that is sufficient for deciding entailment can be computed in polynomial time. © Springer-Verlag 2004.