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Re: RDF/XML Syntax Specification (Revised) W3C Working Draft published

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 20 Dec 2001 13:24:50 -0500
To: mmoran@netphysic.com
Cc: www-rdf-interest@w3.org
Message-Id: <20011220132450Y.pfps@research.bell-labs.com>
From: Mike Moran <mmoran@netphysic.com>
Subject: Re: RDF/XML Syntax Specification (Revised) W3C Working Draft    published
Date: Thu, 20 Dec 2001 18:07:58 +0000

> Peter F. Patel-Schneider wrote:
> 
> [ ... ]
> > 
> > Well let's put it this way.
> > 
> > <rdf:Description rdf:about="http://example.org/common">
> >    <age>10</age>
> > </rdf:Description>
> > 
> > <rdf:Description rdf:about="http://example.org/tom">
> >     <rdf:type rdf:resource="http://example.org/common"/>
> >     <shoesize>7</shoesize>
> > </rdf:Description>
> > 
> > <rdf:Description rdf:about="http://example/jane">
> >     <rdf:type rdf:resource="http://example.org/common"/>
> >     <shoesize>8</shoesize>
> > </rdf:Description>
> > 
> > does *NOT* imply that Tom's age is 10, nor does it imply that Tom has an
> > age.  No ifs, ands, or buts!
> 
>  >
> 
> > Any RDF implemenation that behaves otherwise is broken!
> 
> 
> Ok. So, what does it imply then?

The above implies that the age of common is 10.  Tom and Jane do not
inherit properties from common.

> By your explanation, (using shorthand) it is *not* the case that T isA 
> C, or J isA C. In practical terms, how would I say that T isA C, or J 
> isA C in RDF? I *want* to have shared, inherited, attributes.

Tom is an instance of common.  Tom is not a subClass or subProperty of
common.

RDF does not provide any mechanism for inheriting property values.  

> "tarod@softhome.net" says[1] I can get it by checking for inheritance 
> explicitly using chained (prolog-like it seems) matching operators. 
> However, you seem to say I shouldn't be doing this at all, using the 
> above markup.

If you want to do something outside of RDF, then go right ahead.  However,
that is not RDF.

> I don't wish to troll, but it would seem like inheriting of  attributes 
> is a thing most people would expect to be able to do in RDF, somehow.

Why would one expect that? (And this is a serious question.)

> [1]: http://lists.w3.org/Archives/Public/www-rdf-interest/2001Dec/0095.html
> 
> --
> Mike

peter
Received on Thursday, 20 December 2001 13:26:47 GMT

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