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Re: Guide/Lang: UML as a presentation syntax for OWL

From: Guus Schreiber <schreiber@swi.psy.uva.nl>
Date: Thu, 23 May 2002 15:04:14 +0200
Message-ID: <3CECE8CE.4BD1775C@swi.psy.uva.nl>
To: Christopher Welty <welty@us.ibm.com>
CC: WebOnt WG <www-webont-wg@w3.org>
Christopher Welty wrote:
> 
> 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."

This point was resolved in the followup discussions. 

> 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.

Well, this is true for "transitivity", but not for "inverse" and
"functional role". The latter can be hanled by cardinality constraints
and the former in various indirect ways (see also the discussion in the
UBOT UML/DAML mapping
(http://ubot.lockheedmartin.com/ubot/details/uml_to_daml.html). 

Putting inference notions like transitivity is in the behavior
compartment is an  interesting idea, but would require an explicit
metamodel for our UML use (which is probably a good idea). 
 
> 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"

Agrred. Just to be quick I took some examples from the DAML+OIL
walkthru. 
 
> 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.

To be added when we have decided on syntax. 
 
> 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?

Such relations are very common. I can see no reason why OWL should
forbid it. 
With respect to the duplication of the class symbol: this is a habit
from my teaching classes, where I have that noticed students find this
easier to understand. It is not forbidden in UML, but I have no problems
in using the single-cl;ass style.  

> That's as far as I got.

Thanks for the feedback, Guus

> 
> -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

-- 
A. Th. Schreiber, SWI, University of Amsterdam, Roetersstraat 15
NL-1018 WB Amsterdam, The Netherlands, Tel: +31 20 525 6793 
Fax: +31 20 525 6896; E-mail: schreiber@swi.psy.uva.nl
WWW: http://www.swi.psy.uva.nl/usr/Schreiber/home.html
Received on Thursday, 23 May 2002 09:07:55 GMT

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