Adding formal semantics to the Web Building on top of RDF Schema
Jeen Broekstra, Michel C. A. Klein, Stefan Decker, Dieter Fensel, Ian Horrocks · 2000
Abstract RDF Schema provides means to define vocabulary, structure and constraints for expressing metadata about Web resources. However, formal semantics for the primitives de-fined in RDF Schema are not provided, and the expressivity of these primitives is not enough for full-fledged ontologi-cal modeling and reasoning. To perform these tasks, an addi-tional layer on top of RDF Schema is needed. In this paper, we will show how RDF Schema can be extended in such a way that a full knowledge representation language can be ex-pressed in it, thus enriching it with the required additional expressivity and the semantics of this language. We do this by describing the ontology language OIL as an extension of RDF Schema. First, we give a short introduction to both RDF Schema and OIL. We then proceed to define a Schema to ex-press OIL ontologies in RDF, where the aim is to use exist-ing RDF terminology where possible, and extending RDF(S) where necessary. The result is an RDF Schema definition of OIL primitives, which allows one to express any OIL ontol-ogy in RDF syntax, thus enabling the added benefits of OIL, such as reasoning support and formal semantics, to be used on the Web. We conclude that our method of extending is equally applicable to other knowledge representation formalisms. 1