Information on the Web has grown very quickly. The semantics of this information are becoming explicit and the Semantic Web (Berners-Lee, Hendler, & Lassila, 2001) is emerging. Ontologies provide a formal representation of the real world by defining concepts and relationships between them. In order to provide semantics to Web resources, instances of such concepts and relationships are used to annotate them. These annotations on the resources, which are based on ontologies, are the foundation of the Semantic Web. Because of the Web’s size we have to deal with large amounts of knowledge. All this information must be represented and managed efficiently to guarantee the feasibility of the Semantic Web. Querying and reasoning over instances of ontologies will make the Semantic Web useful.
Marriages of Convenience: Triples and Graphs, RDF and XML in Web Querying