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Re: question

From: Pat Hayes <phayes@ihmc.us>
Date: Thu, 13 Sep 2012 22:33:16 -0500
Cc: Antoine Zimmermann <antoine.zimmermann@emse.fr>, RDF Working Group <public-rdf-wg@w3.org>
Message-Id: <0620C768-578C-4BA8-808C-52A1CF526F7D@ihmc.us>
To: Richard Cyganiak <richard@cyganiak.de>

On Sep 13, 2012, at 7:19 AM, Richard Cyganiak wrote:

> On 13 Sep 2012, at 05:57, Pat Hayes wrote:
>> "The truth of an RDF dataset is defined with respect to a graph extension, a relationship that associates RDF graphs with resources. Think of it as capturing a snapshot of the contents of all g-boxes in the universe of discourse."
> 
> IGEXT stands for Graph EXTension. This parallels property extensions (IEXT) and class extensions (ICEXT) in the current RDF Semantics document. That should explain the first sentence.

Yes, OK. 

> I think the model theory should explicitly say somewhere that IGEXT stands for graph extension, so that we have a pronounceable version of the term.

OK.

> The second sentence is an attempt at relating the semantics at least informally to the term “g-box”, which is likely to be defined in the abstract syntax document (using another word), but unlikely to be given a formal meaning in the semantics.

If its not going to be given a meaning in the semantics, then we need to give an account of how the semantics relates to this idea, but your sentence doesnt do that. The EXT mappings have nothing at all to do with g-boxes and states. (If they did, surely that would also apply to IEXT and ICEXT, right? But it doesn't.) And there is nothing in the semantics which allows IGEXT to change with time: it is defined as a mapping, not a time-dependent mapping.

> Informally, the resources denoted by the names in <name,graph> pairs are g-boxes, and the graphs must be consistent with the “contents” of the denoted g-box. I think that makes the second sentence true.

But that is NOT what the semantics says. If you want to say this, then we need to put some kind of story about gboxes, states and contexts into the semantics. RIght now, this sentence bears no relationship to the semantics. 

Pat

> 
> Best,
> Richard
> 
> 
> 
>> 
>> On the face of it, this seems to be simply false: you just defined truth of a dataset, and you didn't mention graph extensions or g-boxes at all.  Should we simply ignore this sentence, or should the model thoery be modified to account for it?
>> 
>> Pat
>> 
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>> 
>> 
>> 
>> 
>> 
> 
> 
> 

------------------------------------------------------------
IHMC                                     (850)434 8903 or (650)494 3973   
40 South Alcaniz St.           (850)202 4416   office
Pensacola                            (850)202 4440   fax
FL 32502                              (850)291 0667   mobile
phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
Received on Friday, 14 September 2012 03:33:56 GMT

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