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RDF MT: Default values for rdfs:domain and rdfs:range?

From: Jeen Broekstra <jeen.broekstra@aidministrator.nl>
Date: Thu, 28 Mar 2002 14:27:56 +0100
Message-ID: <3CA31A5C.2030106@aidministrator.nl>
To: www-rdf-comments@w3.org

I am rather confused as to what exactly the domain/range of a
property should default to if no explicit domain/range is
specified, and I was hoping your insights could clear it up for
me. I realize that the debate over what exactly constitutes a
resource and what a literal is far from over, but nevertheless I
hope that this practical issue can be resolved.

In the case of rdfs:domain, it is relatively straightforward to
assume that if the domain is not specified, it is in fact
rdfs:Resource. In the case of range the issue becomes cloudier
though, since legal values for objects include literals.
According to the RDF MT we should not confuse between literals
and their denotation, which I take to mean that literals can
conceivably be denoted by URIs. Furthermore, we assume that the
population of the class rdfs:Resource consists of anything that
could be denoted by a URI.

This leads me to think that the range of a property also defaults
to rdfs:Resource, and that any use of that property with a
literal value is within that range. Is this correct? Or do actual
literal values not fall under the category of "things denotable
by URIs"?

If I am correct, would this possibly be another production to add
to the RDFS closure rules in the RDF MT?

(p rdf:type rdf:Property) => (p rdfs:domain rdfs:Resource)
(p rdf:type rdf:Property) => (p rdfs:range rdfs:Resource)

I'd appreciate your help.


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Received on Thursday, 28 March 2002 08:27:40 UTC

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