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Re: rdfms-graph: Food for thought

From: Art Barstow <barstow@w3.org>
Date: Wed, 18 Jul 2001 08:45:45 -0400
To: Aaron Swartz <me@aaronsw.com>
Cc: w3c-rdfcore-wg@w3.org
Message-ID: <20010718084545.A6245@w3.org>
On Mon, Jul 16, 2001 at 08:16:19PM -0500, Aaron Swartz wrote:
> On Monday, July 16, 2001, at 02:48  PM, Graham Klyne wrote:
> 
> >  E.g. when exchanging RDF between systems (the reason for 
> > standardization), do we really want to specify that the 
> > existence of a node, without properties, is significant?  If 
> > so, we must define the significance, and that looks awkward to 
> > me.
> 
> Can you explain why this seems awkward to you? It seems like a 
> perfectly reasonable thing to do to me.
> 
> The alternative seems to declare that:
> 
> <rdf:Description rdf:about="foo" />
> 
> means:
> 
> <foo> rdf:type rdfs:Resource .
> 
> which seems even more awkward.

As a data point it would be interesting to know how
current implementations deal with empty Description
elements.  SiRPAC generates zero triples for the
following test cases:

 <rdf:RDF xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#">
  <rdf:Description/>
 </rdf:RDF>

 <rdf:RDF xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#">
  <rdf:Description></rdf:Description>
 </rdf:RDF>

 <rdf:RDF xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#">
  <rdf:Description about="some_uri"></rdf:Description>
 </rdf:RDF>

I don't see anything in the spec that says whether this behavior
is correct or not.

Art
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Received on Wednesday, 18 July 2001 08:45:45 EDT

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