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

From: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
Date: Wed, 05 Oct 2011 08:47:36 +0200
Message-ID: <4E8BFD88.3070205@liris.cnrs.fr>
To: Richard Cyganiak <richard@cyganiak.de>
CC: "public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
On 10/04/2011 11:30 PM, Richard Cyganiak wrote:
> 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.

I just wrote that this is how "I tend to read" a dataset. It is now
clear that we don't have the same reading.

>> 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.

forget inference, I meant rdf:hasSubgraph rather than log:implies.

I was maintly trying not to mix this debate the the 'complete graph' one :)

  pa


> 
> 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 Wednesday, 5 October 2011 06:48:12 GMT

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