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Re: Why do you want to do that?

From: Frank Manola <fmanola@acm.org>
Date: Thu, 14 Aug 2008 11:15:53 -0400
Cc: "SWIG" <semantic-web@w3.org>, "Richard H. McCullough" <rhm@PioneerCA.com>
Message-Id: <A5E94CB7-A35D-4E4C-A591-6D7E3CA91694@acm.org>
To: Michael Schneider <schneid@fzi.de>

On Aug 13, 2008, at 7:57 PM, Michael Schneider wrote:

> Hi Frank!
> Frank Manola wrote:
>> There aren't any classes in RDF (per se);  in RDFS there are classes,
>> and they can be treated as individuals (which is where we came in,
>> more or less).
> As a minor remark, I think it's easier to understand the situation of
> classes in RDFS, if one states the above sentence the other way  
> around: In
> RDFS there are individuals (aka resources), and some of them can be  
> treated
> as classes, namely those which happen to have a class extension  
> associated
> with them. Analog, some individuals have a property extension  
> associated
> with them, and are therefore properties. An individual may even act  
> as both,
> a class *and* a property, if it has both a class extension and a  
> property
> extension associated. But in any case (as you say), all classes and
> properties are individuals, which exist in the RDFS universe, i.e. the
> domain of discourse.


You may be right about the sentence "direction".  My main point was  
simply that, strictly speaking, the "class" concept isn't part of RDF  
(it isn't in the "rdf:" vocabulary);  classes are only introduced when  
you get to the "rdfs:" vocabulary, as a "semantic extension".


>> That is, in RDFS a class is a resource (like
>> everything else that can be referred to in RDFS), and resources can  
>> be
>> the subjects of triples.
>> --Frank
> Cheers,
> Michael
Received on Thursday, 14 August 2008 15:16:44 UTC

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