OWL Rules, OK?

Although the OWL Web Ontology Language adds considerable expressive power to the Semantic Web it does have expressive limitations, particularly with respect to what can be said about properties. One possible solution to this problem is to extend OWL with some form of “rules” language. Several different integration frameworks have already been proposed, each having different features and limitations. Regardless of which framework is eventually chosen, it is essential that the integrated language has a clear declarative semantics that is independent of any particular implementation technique.