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Re: why I don't like named graph IRIs in the DATASET proposal

From: Richard Cyganiak <richard@cyganiak.de>
Date: Tue, 4 Oct 2011 22:30:32 +0100
Cc: "public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
Message-Id: <562DE541-3A40-495B-B82A-7A54049B2F87@cyganiak.de>
To: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
On 4 Oct 2011, at 21:48, Pierre-Antoine Champin wrote:
>> RDF Semantics currently doesn't have the power to fix the
>> denotation of *anything* (except the RDF(S) built-ins),
> 
> and all literal values...

Ok, you got me there ;-)

>> and *always*
>> defers to convention for establishing the connection between IRIs and
>> things. RDF works nevertheless. Why should it be any different for
>> graphs?
> 
> Well, if graphs in a dataset are g-snap, then they look very much like
> literals to me, and I would tend to read
> 
>  <some-uri> { :a :b :c }
> 
> as something like
> 
>  <some-uri> owl:equals " :a :b :c . "^^rdf:turtle

I disagree. The latter amounts to an assertion that <some-uri> denotes an RDF graph. The former doesn't assert anything (or shouldn't, in my view). It's just a graph associated with a URI.

> Now, if graphs are g-boxes, I would rather read
> 
>  <some-uri> { :a :b :c }
> 
> as something like
> 
>  <some-uri> rdf:hasCurrentGSnap [
> 	log:implies " :a :b :c . "^^rdf:turtle
>  ]
> 
> where rdf:hasCurrentGSnap would have rdf:GBox as its domain, so I can
> *at least* infer that <some-uri> denotes *some* g-box.

I do not like the idea of inferring anything from the graph names in RDF datasets. That way madness lies.

For starters: In what graph would you like to store those inferences?

> In any case, I do not see how what I propose implies something radically
> different from the kind of inference that already exist in RDF.

Inference is the process of deriving new statements from statements whose truth is known or can be presupposed. In an RDF dataset, you cannot presuppose the truth of anything  the graphs are not asserted but merely collected for data management purposes.

Inference is defined over RDF graphs, not over collections of unasserted RDF graphs.

Best,
Richard
Received on Tuesday, 4 October 2011 21:31:01 GMT

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