• Links - Web Ontology Language ( OWL2 )

Revised Nov 1 2008: Draft of OWL2 specs.

The recent drafts of the OWL2 specification describe some important changes from OWL1. In a nutshell,

The structural specification of OWL 2 provides the foundation for the implementation of OWL 2 tools such as APIs and reasoners. ... This document also defines the functional-style syntax, which closely follows the structural specification and allows OWL 2 ontologies to be written in a compact form.

From a Semantic Web standpoint, the two key ideas are 'reasoners' and 'compact form', which is essentially a functional-style language syntax equivalent to/mappable to the XML representation. See the OWL 2 Web Ontology Language: Structural Specification and Functional-Style Syntax, especially the sections for Class Expressions and the Axiom Class. Also see examples of the Functional-Style Syntax ( FSS ? ) in Mapping to RDF Graphs.

OWL2 may extend OWL1 with "a small but useful set of features", but it seems to be a huge extension in terms of the usability of OWL ontologies. For the first time ever, OWL structures can be read and written by human beings ... even if the human beings are only programmers. :-)

Some RDF Links

W3.org's specification of "a precise semantics, and corresponding complete systems of inference rules, for the Resource Description Framework (RDF) and RDF Schema (RDFS)".

The Virtuoso Open-Source Edition - massive ( 48 Meg ) but interesting. From the site:

Virtuoso is an innovative Universal Server platform that delivers an enterprise level Data Integration and Management solution for SQL, RDF, XML, Web Services, and Business Processes..