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Re: Settheoretical interpretation of the RDF-schema possible?

From: Wolfram Conen <conen@gmx.de>
Date: Tue, 05 Jun 2001 17:43:30 +0200
Message-ID: <3B1CFE22.FA4F5C57@gmx.de>
To: Christian Kruggel <kruggel@kbs.uni-hannover.de>
CC: www-rdf-interest@w3.org
Christian Kruggel wrote:
> This raises the question if then rdfs:Resource is also an instance of
> itself for the property of being instance of oneself is a property of a
> class and such properties are inherited along the subClassOf-relation.
> If there was just one class that's an instance of itself this would be
> no surprise. All objectoriented programminglanguages have to define such
> a class. But it would be useless and confusing if the RDF-schema
> specifies at least two classes to be instances of themselves.

Hm, ok, could it be that your problem comes from the fact that RDFS
describes an abstract world by means of elements of this world?  That
is, there are "abstract" concepts like rdfs:Class that are also "named"
with a URI rdfs:Class, which itself is part of the universe of
discourse, and, thus, must be placed somewhere in the (abstract) class
hierarchy. The same is true for rdfs:Resource -- it is a class (from the
perspective of the abstract class system), but the "name" of the concept
(the string/URI/"resource") is also a resource (and, thus, has to be a
member of the abstract class rdfs:resource). So, this might be
considered confusing, but I can not see that it is problematic. Maybe
you can be more specific and try to tell, what does not work in your
attempt to give a proper set-theoretical interpretation?

> 
> At the moment I think that the RDF-schema enforces the equalization of
> instances and classes for any subClassOf rdfs:Resource inherits the
> propery of being instance of itself. Am I doing wrong?
> 

If I understand this correctly, you are wrong, because the fact that the
thing "rdfs:resource" is a member of the (abstract) class
"rdfs:resource" is NOT a property of the class, but a property of an
element of the class (the URI/thing/name/string/Whatever
"rdfs:resource"), and, thus, nothing is inherited in the way you assume.

Maybe this helps a little bit? (sorry for the somewhat fuzzy
terminology, maybe your approach to give a set-theoretic interpretation
of RDFS will help to clarify it).

	Wolfram
Received on Tuesday, 5 June 2001 11:41:41 GMT

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