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Re: rdfs:subClassOf and metaclasses

From: Piotr Kaminski <piotr@ideanest.com>
Date: Wed, 03 Jul 2002 09:28:14 -0700
To: Brian McBride <bwm@hplb.hpl.hp.com>, www-rdf-comments@w3.org
Message-id: <012501c222b0$38042760$ada15018@transfinity>

From: "Brian McBride" <bwm@hplb.hpl.hp.com>
> The first step in this process is to establish exactly what the problem
> is.  The only "problem" I see below is that you don't think the current
> proposal "makes sense".  We need something a little stronger than that,
> e.g. an internal contradiction.


I'm still thinking through the ramifications and hope to come up with
something stronger soon.  I think the only way to reach an internal
contradiction is through the domain and range constraints, but I'm not sure
they're strong enough for the job.  I'm convinced I could find something in
DAML+OIL, but that's a much weaker argument.  At this point some help from
people who've been doing this kind of stuff much longer than me would be
very welcome.

> i.e. I conclude that the class of resources defined by Brian is a subClass
> of the resources defined by Piotr, i.e. every resource defined by Brian is
> also a resource defined by Piotr. That is not a valid inference.

Precisely.  You're getting an unwanted inference, so there's an error in the
model you started out with.  It's just a question of how you apply the
rule -- this is exactly the situation described in RDF Model Theory section
4.3.  And if you want to inherit from my resource class, then your metaclass
had better inherit from mine.  :-)

        -- P.

--
  Piotr Kaminski <piotr@ideanest.com> http://www.ideanest.com
  It's the heart afraid of breaking that never learns to dance
Received on Wednesday, 3 July 2002 12:41:58 GMT

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