A posting from Dan Connolly to the W3C 'www-rdf-logic' mailing list announces the formation of a new Web Ontology Working Group within W3C. The Web Ontology (WebOnt) Working Group has been chartered to design a web ontology language "that builds on current web languges that allow the specification of classes and subclasses, properties and subproperties (such as RDFS), but which extends these constructs to allow more complex relationships between entities including: means to limit the properties of classes with respect to number and type, means to infer that items with various properties are members of a particular class, a well-defined model of property inheritance, and similar semantic extensions to the base languages. The web ontology language must support the development and linking of ontologies together, in a web-like manner. The products of this working group must be supported by a formal semantics allowing language designers, tool builders, and other 'experts' to be able to precisely understand the meaning and 'legal' inferences for expressions in the language. The language will use the XML syntax and datatypes whereever possible, and will be designed for maximum compatibility with XML and RDF language conventions."

The W3C Web Ontology Working Group will be chaired by Jim Hendler (University of Maryland); the W3C Working Group team contact is Dan Connolly.

From the announcement:

This Working Group, part of the Semantic Web Activity, will focus on the development of a language to extend the semantic reach of current XML and RDF meta-data efforts. In particular, in a recent talk on the Semantic Web, Tim Berners-Lee, Director of the W3C, outlined the necessary layers for developing applications that depend on an understanding of logical content, not just human-readable presentation. This working group will focus on building the ontological layer and the formal underpinnings thereof.

Such language layers are crucial to the emerging semantic web, as they allow the explicit representation of term vocabularies and the relationships between entities in these vocabularies. In this way, they go beyond XML, RDF and RDF-S in allowing greater machine readable content on the web. A further necessity is for such languages to be based on a clear semantics (denotational and/or axiomatic) to allow tool developers and language designers to unambiguously specify the expected meaning of the semantic content when rendered in the Web Ontology syntax.

The Working Group shall start by evaluating the technical solutions proposed in the DAML+OIL draft. If in this process the Working Group finds solutions that are agreed to be improvements over solutions suggested by DAML+OIL, those improved solutions should be used.