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Re: comments on "SPARQL Query Language for RDF" (Non-respect for RDF Semantics)

From: Dan Connolly <connolly@w3.org>
Date: Wed, 07 Sep 2005 22:26:54 -0500
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: public-rdf-dawg-comments@w3.org
Message-Id: <1126150014.4430.63.camel@dirk>

Thanks for the careful review... we have something of a back-log
of comments, so it may be some weeks before we can respond to
all of your points in substance.

Meanwhile, I'd like to know more about one of your points...

On Wed, 2005-09-07 at 21:26 -0400, Peter F. Patel-Schneider wrote:
> ISSUE 1 (show-stopper):  Non-respect for RDF Semantics
> For example, querying
> G1	ex:a ex:b ex:c .
> 	_:a ex:b ex:c .
> with the triple pattern
> 	?x ex:b ex:c .
> will result in two matches, one for ex:a and one for _:a.
> Querying 
> G2	ex:a ex:b ex:c .
> with the same triple pattern will result in only one match, for ex:a.  However,
> G1 and G2 are equivalent with respect to simple interpretations (and thus also
> for RDF interpretations, RDFS interpretations, and OWL interpretations).

The technical point you make is clear. If you can elaborate on what
makes this a show-stopper, i.e. what one would want to do with SPARQL
that one cannot do with the design as is, that would be even
more helpful.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Thursday, 8 September 2005 03:27:00 UTC

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