Thanks for a fascinating overview. My comment on the webmeeting chat line was slightly facetious when I stated that: “If OWL added identifiers as you suggest, that would break Tim Berner-Lee's underlying model for Web architecture”, but I think that you hit the heart of one of the problems that I have with OWL and with the W3C axioms about information modelling: that is the failure to distinguish between:
- a URL as an identifier of something, (in the terms you refer to in slide 34 ); and
- a URL that is the “something” (a resource)
and the fact that you can’t actually make any assertion about a URL being considered as an identifier.
Although not designed as a standard for inferences and reasoning, the ISO Topic Maps standard does have an explicit mechanism for capturing and managing identity (using the concept of published subject identifiers), in the ways you describe are needed. I’m not sure what other specs out there do likewise, except for the humble URN…
In either case, we still have the problem of what you called “relative uniqueness” rather than, presumably, absolute uniqueness.
I look forward to seeing you at the Ontology Summit next week!
Peter F Brown
Chair, CEN eGovernment Focus Group
Co-Editor, OASIS SOA Reference Model
Lecturer at XML Summer School
+43 676 610 0250