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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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