W3C home > Mailing lists > Public > semantic-web@w3.org > December 2007

Re: RDF/XML and named graphs

From: Phil Archer <parcher@icra.org>
Date: Fri, 14 Dec 2007 09:15:51 +0000
Message-ID: <476249C7.8010109@icra.org>
To: Semantic Web <semantic-web@w3.org>

I'm delighted to see this discussion take place although unable to make 
much of a contribution to it as it's a little beyond my skill level. 
However, I wonder whether any of the actual or potential problems of 
backwards compatibility might be ameliorated if the graph property were 
from a different namespace than RDF? i.e. ex:graph rather than 
rdf:graph? How would a generic SW tool handle that?

The POWDER WG charter[1] makes it clear that we are 'not allowed' to 
make any amendments to the RDF core... but we would be within out 
charter to suggest an extension that could be safely ignored by generic 
parsers and processed by POWDER-aware apps.


[1] http://www.w3.org/2007/02/powder_charter

Jeremy Carroll wrote:
> Alan Ruttenberg wrote:
>> I was thinking less of whether it would be considered legal by 
>> parsers, but whether the semantics would be corrupted.
>> Initially you have triples segregated into graphs, but for an old 
>> parser you have a single graph and some extra triples.
>> Could there be nasty misunderstandings?
> I think there could be, and one would need to be careful.
> In RDF as in the recommendations, it is fairly hard to have different 
> semantic force. This can be achieved by using separate documents. For 
> example, the RDF Test Cases, are described with a Manifest file (which 
> is in RDF), and is intended to be read as an assertion of fact, or 
> intent, or even as a performative "we hereby bless the following tests" 
> by the RDF Core WG, and the W3C. The data files for the tests appear in 
> a similar way on the Web server, and are intended to be read as 
> examples, without any intent of their meaning being taken seriously.
> If the author of the triples means all of them: i.e. they are all true 
> in the author's world view, then the motive for separating them into 
> different graphs maybe to make them easier to read or process - so for 
> example metadata may be best kept separate from data or metametadata.
> But if someone else reads it all at a single level, it's not that 
> anything is false ....
> Jeremy

Phil Archer
Chief Technical Officer,
Family Online Safety Institute
w. http://www.fosi.org/people/philarcher/
Received on Friday, 14 December 2007 09:16:05 UTC

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