- From: Christopher Welty <welty@us.ibm.com>
- Date: Mon, 20 May 2002 15:24:39 -0400
- To: Ian Horrocks <horrocks@cs.man.ac.uk>
- Cc: www-webont-wg@w3.org, www-webont-wg-request@w3.org
OK, Ian and I had a discussion off-line and I have been corrected. I said I disagree with this statement in Guus' proposal: "[LANG note: proposal to drop "primitive classes" and use "class" instead. This implies that, by default, classes are primitive.] I retract my disagreement (in other words I now agree with the statement). -Chris Dr. Christopher A. Welty, Knowledge Structures Group IBM Watson Research Center, 19 Skyline Dr. Hawthorne, NY 10532 USA Voice: +1 914.784.7055, IBM T/L: 863.7055 Fax: +1 914.784.6078, Email: welty@us.ibm.com Ian Horrocks <horrocks@cs.man.ac.uk> Sent by: www-webont-wg-request@w3.org 05/16/2002 04:00 PM Please respond to Ian Horrocks To: Christopher Welty/Watson/IBM@IBMUS cc: www-webont-wg@w3.org Subject: Re: Guide/Lang: UML as a presentation syntax for OWL I agree with most of what Chris has written w.r.t. UML (although I don't pretend to be an expert). I disagree, however, with the use of the term "primitive" to describe RDF (or DAML+OIL/OWL) classes. It is not true even of RDF that it "does not provide a way to specify sufficient conditions for class membership" (as stated in the compliance level 1 document). E.g., if class C is the domain of property P, then from P(x,y) I can infer C(x). Of course it is "even less true" of DAML+OIL/OWL: having a "primitive definition" (i.e., a subClass axiom) in one place doesn't preclude the possibility of specifying sufficient conditions elsewhere in the ontology. For this reason, I believe that terms like "primitive" and "defined" should be avoided. Ian On May 15, Christopher Welty writes: > In reference to > http://www.swi.psy.uva.nl/usr/Schreiber/docs/owl-uml/owl-uml.html > > (are there reasonable tools for suggesting changes in HTML like there is > in MS Word?? > > > My comments: > > As I mentioned in my previous note > (http://lists.w3.org/Archives/Public/www-webont-wg/2002May/0100.html), I > disagree with the note [LANG note: proposal to drop "primitive classes" > and use "class" instead. This implies that, by default, classes are > primitive.] Since UML will only be able to specify primitive OWL > classes, I believe we should be specific about this in the document. Thus > the first paragraph of the section:UML notations for OWL Lite, > subsection:Classes and subclasses should read: > "A primitive OWL class is shown in a similar fashion as a UML class. Note > that ontologies typically do not specify class behavior, so the operation > compartment will stay empty. Classes may have primitive subclasses." > > The second sentence is not strictly true, since in OO languages most of > what we can specify in OWL, such as inverses, transitivity, functional > roles, etc. would need to be implemented. "Inference" per se is not > something one can specify directly in UML, and we may want to have some > conventions of our own for specifying standard inferences - from a UML > perspective I think these things would belong in the "class behavior" > section. > > Let's try to use decent examples, because they become canonical. Male and > Female are not subclasses of Animal. Let's change the subclasses to > "Mammal" and "Reptile" > > Some details of the level 1 language should probably be worked out before > we decide on many of the finer points. > > We should show the precise OWL for each UML diagram. > > The Animal has-parent Animal diagram is confusing, first of all my > understanding of UML was that associations to the class require a single > box, with a line going from that box out and then back. Second, this is a > cycle - does OWL allow cycles? > > That's as far as I got. > > -Chris > > Dr. Christopher A. Welty, Knowledge Structures Group > IBM Watson Research Center, 19 Skyline Dr. > Hawthorne, NY 10532 USA > Voice: +1 914.784.7055, IBM T/L: 863.7055 > Fax: +1 914.784.6078, Email: welty@us.ibm.com
Received on Monday, 20 May 2002 15:25:45 UTC