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Re: RDF/XML Syntax Question: Label on an RDF Object being a literal

From: David Booth <david@dbooth.org>
Date: Mon, 01 Mar 2010 12:55:23 -0500
To: Damian Steer <pldms@mac.com>
Cc: Svante Schubert <Svante.Schubert@Sun.COM>, Semantic Web <semantic-web@w3.org>, Dan Brickley <danbrickley@gmail.com>
Message-ID: <1267466123.5216.31118.camel@dbooth-laptop>
On Sun, 2010-02-28 at 22:19 +0000, Damian Steer wrote:
> On 28 Feb 2010, at 18:04, Svante Schubert wrote:
> 
> > I got a question on RDF/XML syntax.
> > I would like to put an rdfs:label on an RDF object being a literal.
> > 
> > In RDF I read that rdfs:label takes as input an rdfs:Resource
> > http://www.w3.org/TR/rdf-schema/#ch_label
> > and found that the literal (rdfs:Literal ) is a subclass an rdfs:Resource
> > http://www.w3.org/TR/rdf-schema/#ch_literal
> > 
> > Therefore it should be possible to do so.
> 
> Hi Svante,
> 
> This is a rather tricky question, but I think the simplest answer is: you can't do that. A literal can't be an object
> 
> ( The more accurate answer is that a literal can be an object, but you can't write that directly in rdf syntax. For example:
> 
>   _:date owl:sameAs "1980-09-02"^^xsd:date . _:date ex:readableLabel "2. September 1980" )
> 

Right, however the word "object" may be a bit confusing here, as it is
overloaded.  If you think of an RDF triple as being

 <subject> <predicate> <object> .

then in RDF/XML a literal cannot occupy the <subject> position of the
triple, though it may occupy the <object> position.  Damian's example
above provides a work-around for this unfortunate restriction.



-- 
David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.
Received on Monday, 1 March 2010 18:22:29 UTC

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