> -----Original Message-----
> From: ext Sean B. Palmer [mailto:[log in to unmask]]
> Sent: 13 January, 2003 22:34
> To: [log in to unmask]
> Subject: Re: rdfs:isDefinedBy revisited
>
> > My understanding of the outcome of the long debate about
> > rdfs:isDefinedBy was that the value can be _any_ resource
> > which in some unspecified way or other "defines" the subject
> > resource.
>
> Yep. According to the RDF Schema for RDF Schema [2] the range
> and domain
> for rdfs:isDefinedBy is rdfs:Resource, and the semantics
> presented for the
> property [3] in the RDF VDL 1.0 WD are quite loose. Hmm...
> note that it
> does say "indicates *the* resource defining the subject
> resource" [emphasis
> added], which seems to imply that you can only specify a single
> rdfs:isDefinedBy property for a resource. Might be worth an
> rdf-comments
> mail, but I reckon it's a typo (should be "a resource").
It's surely a typo. One can have multiple rdfs:isDefinedBy
values, where each provide a component of the definition
(e.g. just one example, separate RDF Schemas that define
labels and comments for particular languages, where a given
term then has definition in as many schemas as there are
languages defined.
I'll ping the editor on this.
> But that's irrelevant: I don't think that you need to worry about
> specifying an rdf:type for that resource. Why would it be
> useful to do so?
> What's the justification?
Knowing how to process it. If it is asserted that the resource is
an RDF Schema, then an RDF application could directly assimilate the
statements contained therein. If it is XHTML, an application can
open a browser. etc. etc.
Of course, given the current imprecise nature of the web (as opposed
to the semantic web) just because a given resource is defined in
RDF to be of a certain type, does not mean that you will necessarily
get anything comparable to that type when dereferencing its URL
(presuming it's actually denoted by a URL that can be dereferenced)
given the loose and free nature of "representations" and
content negotiation.
It may be asserted to be of type RDF Schema but you might very well
get XHTML depending on the whims of the server...
> > I _could_ have a non-RDF/XML document as the object of
> > an rdfs:isDefinedBy statement: an HTML document, a text file,
> > a graphic, even a non-Web retrievable resource. Is that correct
> > please?
>
> Yes, you could.
And that resource need not even be a document. It could be e.g.
a person or organization. I.e. any resource from which
authoritative defining knowledge might be obtained, regardless
as to whether it is web retrievable or machine readable.
It can be *any* resource. I.e. anything in the Universe that
can be denoted by a URIref.
Cheers,
Patrick
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