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Re: ISSUE-30: How does SPARQL's notion of RDF dataset relate our notion of multiple graphs?

From: Pat Hayes <phayes@ihmc.us>
Date: Sat, 16 Apr 2011 16:50:15 -0500
Cc: Ivan Herman <ivan@w3.org>, RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <E5214E03-AB18-42DD-956A-718E3B4D6DD2@ihmc.us>
To: Richard Cyganiak <richard@cyganiak.de>

On Apr 16, 2011, at 11:23 AM, Richard Cyganiak wrote:

> Pat,
> 
> On 14 Apr 2011, at 18:09, Pat Hayes wrote:
>> The 'naming' of graphs in SPARQL is a wholly SPARQL-local business,
> 
> What I want to see is an adoption of SPARQL's “naming” mechanism into the RDF data model. This would make this “SPARQL-local business” a proper part of RDF.

OK, but then it would have to somehow be reconciled with the RDF model theory. In its present form it cannot be so reconciled, as it explicitly denies any connection to the model theory. 

> 
>> unrelated to RDF semantics 
> 
> Correct, and that's not a bug, it's a feature.

No, it is a problem. To be unrelated to the normative semantics is never a feature. 

> This part of SPARQL is successful and useful despite being disconnected from the RDF Model Theory. RDF Datasets as they are defined in SPARQL have no impact on entailments, and therefore do not require a relation to the RDF Model Theory.

The model theory is the semantics of RDF. It bears on any operation on RDF that is sensitive to the meanings of URIs or triples or literals. It is not purely concerned with entailments. 

> Semantic extensions (like Antoine's import proposal) can of course extend the RDF Model Theory in order to explain their extended notion of entailment.

Of course. However, Antoine's import proposal does not actually work as stated, for the reasons I have already pointed out. 

> 
>> and therefore to any RDF content. 
> 
> This does not follow. “RDF content” is the triples in the data model.

No, RDF content is the semantic content of the triples in the data model. The RDF model theory is normative. It is not something that can be handily ignored just because someone does not like it. 

Pat

> 
> Best,
> Richard

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Received on Saturday, 16 April 2011 21:50:46 GMT

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