Re: semantics document revised

Pat's new version is considerably better than the previous one, but it
still has serious problems that make the claim in section 4.3 false,
including:
- The conditions on rdfs:domain, rdfs:range, rdfs:subClassOf, and
  rdfs:subPropertyOf are too weak.
- There are many divergences between the constructs described in the
  document and the constructs of OWL.
- The definition of sameXXAs, and some other OWL constructs, should be iff,
  perhaps restricted to owl:Thing.  If not restricted to owl:Thing, then
  the domains and ranges of the properties have to be removed.
- Restrictions have to be relative to owl:Thing.

The treatment of lists is much stronger than needed for OWL.

Ian and I pointed out most of these problems on Friday, and, indeed, most
of them have been pointed out before.


From: pat hayes <phayes@ai.uwf.edu>
Subject: semantics document revised
Date: Tue, 10 Sep 2002 01:26:01 -0700

> There is a new version of the OWL/RDF semantics document at
> 
> http://www.coginst.uwf.edu/users/phayes/RDFS2OWL-G.html
> 
> This has been much changed in response to comments and suggestions by 
> Ian and Peter, but they have not had a chance to review it yet so it 
> may have some bugs in it still. In particular the 'strong' semantic 
> conditions in section 4  may need to be strengthened so that 
> rdfs:subClassOf is 'iff' on owl:Class. I am genuinely unsure quite 
> how strong the full OWL semantic conditions are intended to be.
> 
> BTW, what was once called GHOWL is now the 'weak' semantics in section 3.


Instead of going through yet another set of detailed comments, I direct
your attention to the enclosed semantics document, which is a revision of
one I sent to the working group a while ago.

Peter F. Patel-Schneider
Bell Labs Research