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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.

Michael--

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".

--Frank

>
>
>> 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 GMT

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