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Re: statements about a graph (Named Graphs, reification)

From: Richard Cyganiak <richard@cyganiak.de>
Date: Tue, 4 Sep 2007 14:01:42 +0200
Message-Id: <D9EE14D0-F427-424A-B0CF-4B475FAFB89C@cyganiak.de>
Cc: "K-fe bom" <u9x3n_15so@hotmail.com>, <semantic-web@w3.org>
To: "Michael Schneider" <schneid@fzi.de>


On 4 Sep 2007, at 13:02, Michael Schneider wrote:
>> I find that making statements about the URI of the document (in your
>> case, the HTML page containing the RDFa) works for me. It isn't
>> technically *quite* the same as annotating the named graph, but often
>> I find it actually more appropriate to make statements about the
>> document, not the graph.
>
> But what I am unclear about is, what has this approach to do with the
> NamedGraphs idea?

I interpret a set of documents (e.g. the web) as a set of named graphs.

> AFAICS, what you suggest here is just of the form: "Take
> some URI, and interprete it in a way that it denotes some RDF  
> graph, and
> then start to make assertions about this resource in the form of RDF
> triples."

Yes. That's the one-sentence description of named graphs.

> This happily maps into the current RDF framework and its model
> theoretic semantics.

No. Using vanilla RDF without semantic extensions, you cannot record  
the fact that some triple <a> <b> <c> is in some graph <d>. Named  
graphs is a minimum semantic extension that lets you do this.

Richard


> And in practice, if I find in the SemWeb an RDF
> description about some URI, which turns out to be an URL of some RDF
> document, than it looks pretty natural to me that the given RDF  
> description
> is a description of at least this RDF document. And from this, it  
> is not a
> big step to regard the RDF description to be a description of the  
> RDF graph
> represented by that RDF document. So, it looks to me that I can go  
> pretty
> well with this approach in existing RDF, without introducing some  
> notion of
> a NamedGraph into the RDF framework. Or did I overlook something?
>
> Cheers,
> Michael
>
> --
> Dipl.-Inform. Michael Schneider
> FZI Forschungszentrum Informatik Karlsruhe
> Abtl. Information Process Engineering (IPE)
> Tel  : +49-721-9654-726
> Fax  : +49-721-9654-727
> Email: Michael.Schneider@fzi.de
> Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555
>
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>
Received on Tuesday, 4 September 2007 12:01:59 UTC

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