Common Languages for Web Semantics

RDF is a language to express propositions on the WWW and OWL is a language for defining Web ontologies. It seems that RDF and OWL have established themselves as a standard in Semantic Webs. However, endeavors to describe ontology in OWL are revealing the extent of the language capability in practical views. In this paper. firstly we give an overview of basic assumptions as knowledge representation languages for Semantic Webs, and then point out several basic and problematic issues of OWL mainly arose from the difference of the foundation among languages. They are captured by our own experience of developing an object oriented language for Semantic Webs and its applications. They are solved in our language by means of i) explicit descriptions of role concepts, ii) auto-epistemic local closed world assumption. iii) ternary truth values, and iv) unique name assumption for atomic objects. Finally, we envision the direction of language development for web semantics with reviewing Common Logic.