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Re: rdfs:Class vs. daml:Class ?

From: Steven Gollery <sgollery@cadrc.calpoly.edu>
Date: Mon, 08 Apr 2002 12:34:06 -0700
Message-ID: <3CB1F0AE.E38033A6@cadrc.calpoly.edu>
To: www-rdf-logic@w3.org

I don't have the background to discuss most of the fallacies you mention , but I
would like to talk about one of them:

Pat Hayes wrote:

> 21. The fact that rdfs:Resource is both an instance and a superclass
> of rdfs:Class is a "problem".

One of the things I was working on when I started looking at RDF and DAML was to be
able to generate RDF/DAML from UML system models. I thought it might be useful to
consider RDF and DAML from a metamodeling perspective, so that there was a
correspondence to OMG's layered metamodeling architecture. Then I could translate
from the MOF in the XMI representation of the UML model, to an equivalent set of
instances of an RDF metamodel.

But my effort foundered on points exactly like the one you mention: the way I
understand layered metamodel architectures, for "class A" to be an instance of
"class B", B must be on a higher metamodel layer than A. But for class A to be a
superclass of class B, both classes must be on the same layer. This is true in the
metamodeling world, but apparently not a consideration in the RDF world.

So whether this is a problem or not depends on what we're trying to accomplish.
Which is true of everything, I suppose.

Steven Gollery
Received on Tuesday, 9 April 2002 05:08:15 UTC

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