- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Wed, 5 Jun 2002 18:39:29 -0400
- To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>, Enrico Motta <e.motta@open.ac.uk>
- Cc: Deborah McGuinness <dlm@ksl.stanford.edu>, Webont <www-webont-wg@w3.org>
At 12:29 AM +0200 6/6/02, Frank van Harmelen wrote: >Enrico Motta wrote: >> >> Deborah, >> >> Just one minor comment. The document does not explicitly say whether >> subclassOf hierarchies can have cycles (like daml+oil) or not (like >> rdfs). Because subclassOf properties are listed under Rdfs features, >> one would think that no cycles are allowed, while the presence of >> sameClassAs in the language leads one to think that cycles are OK. > >Even RDFS now allows cycles in the class hierarchy. >We might point out in our own document that as a result, >sameClassAs is simply syntactic sugar (but: useful syntactic sugar) >for something that could already be done without it (even in RDF Schema). > >Frank. ---- Frank - not sure if this is true in a multi-ontology setting jim:foo owl:sameClassAs frank:bar. can be used in cases where the only way to create the cycle would be for me to call you up and ask you to put a pointer to my subclass in your document. So I think some of these things (the "equivalentTo family") are important for the cross ontology requirement as well as within ontologies. -JH -- Professor James Hendler hendler@cs.umd.edu Director, Semantic Web and Agent Technologies 301-405-2696 Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) Univ of Maryland, College Park, MD 20742 240-731-3822 (Cell) http://www.cs.umd.edu/users/hendler
Received on Wednesday, 5 June 2002 18:39:49 UTC