- 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