On integrating rules into the Semantic Web

AbstractThe Semantic Web effort of W3C aims at enhancing the web with reasoning capabilities. The approach is to design several tightly related (“layered”) languages for description of web resources and reasoning about them. This note briefly surveys the roles of the languages proposed so far: RDF, RDF Schema and the Web Ontology Language OWL, and refers to their known relations to the Description Logics. The next, not yet existing, layer of the Semantic Web, should be a rule layer. Several rule languages may be needed, depending on the applications. Horn logic is often considered a starting point for further extensions. Thus, for adding rules on top of the web ontology layer a relevant question is how to combine Horn logic with Description Logics. Some known approaches to this problem are briefly summarized