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Re: problem with blank node identifiers and rdf:nodeID

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Thu, 28 Nov 2002 21:10:26 +0000 (GMT)
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
cc: bwm@hplb.hpl.hp.com, www-rdf-comments <www-rdf-comments@w3.org>
Message-ID: <Pine.GSO.4.44.0211282108110.22682-100000@mail.ilrt.bris.ac.uk>

On Thu, 28 Nov 2002, Peter F. Patel-Schneider wrote:

> From: Jan Grant <Jan.Grant@bristol.ac.uk>
> Subject: Re: problem with blank node identifiers and rdf:nodeID
> Date: Thu, 28 Nov 2002 17:32:47 +0000 (GMT)
>
> > To be clear: Peter's correct that there's a bug in the transformation
> > specification in the syntax document. A "name mangler" is _not_
> > forbidden by the specification, however, since:
> >
> > http://www.w3.org/TR/2002/WD-rdf-syntax-grammar-20021108/#section-Data-Model
> >
> > says
> >
> > [[
> > This model illustrates one way to create a representation of an RDF
> > Graph from an RDF/XML document. It does not mandate any implementation
> > method - any other method that results in a representation of the same
> > RDF Graph may be used.
> > ]]
>
> The problem is, however, that the document does not present a way of
> producing a unique class of equivalent RDF graphs from an RDF/XML
> document.  For example,
>
> <rdf:RDF xmlns:rdf="..."
>          xmlns:ex="...">
>
> <rdf:Description rdf:nodeID="n1">
>  <ex:foo>
>   <rdf:Description />
>  </ex:foo>
> </rdf:Description>
>
> </rdf:RDF>
>
> could produce either of the two following RDF graphs
>
> _:x1 <ex:foo> _:x1 .
>
> or
>
> _:x1 <ex:foo> _:x2 .
>
> which are not equivalent.

That's why the "Blank Node Identifier" generation needs documenting; and
the use of the nodeID attribute value needs modifying when turned into a
blank node identifier, too.

The original text predates nodeID; the doc needs a bugfix but I don't
think it's a large one. Providing that nodeID attribute-values can't
clash with generated ids, everything else should be ok, right?


-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/
perl -e 's?ck?t??print:perl==pants if $_="Just Another Perl Hacker\n"'
Received on Thursday, 28 November 2002 16:11:50 GMT

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