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Re: rdfs:Graph ? comment on http://www.w3.org/TR/rdf11-concepts/#section-dataset and issue 35

From: Sandro Hawke <sandro@w3.org>
Date: Fri, 26 Jul 2013 19:08:14 -0400
Message-ID: <51F3015E.5080303@w3.org>
To: Jeremy J Carroll <jjc@syapse.com>
CC: Eric Prud'hommeaux <eric@w3.org>, "www-archive@w3.org" <www-archive@w3.org>, Pat Hayes <phayes@ihmc.us>, "Peter F. Patel-Schneider" <pfpschneider@gmail.com>, Andy Seaborne <andy@apache.org>
On 07/26/2013 06:21 PM, Jeremy J Carroll wrote:
> Ah, and I just came across some other relevant text:
>
> http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#namedGraphs
>
> The |FROM NAMED| syntax suggests that the IRI identifies the 
> corresponding graph, but the relationship between an IRI and a graph 
> in an RDF dataset is indirect.*The IRI identifies a resource, and the 
> resource is represented by a graph (or, more precisely: by a document 
> that serializes a graph).*
>
>
> Given that the text in bold is already normative,

Normative for SPARQL UPDATE is not the same as normative for RDF ...

> am I detecting some part of the RDF WG that somehow wishes to go back 
> on that.

I'm not sure we're going back on that so much as noticing how vague that 
text is.  It doesn't rule out that the resource is the graph (as in the 
case you are maybe saying you want).

> I do not believe that my ideal outcome would be no more than the text 
> in bold.
>

I can't understand your double negative, sorry.

       -- Sandro

>
>
> Jeremy J Carroll
> Principal Architect
> Syapse, Inc.
>
>
>
> On Jul 26, 2013, at 9:37 AM, Jeremy J Carroll <jjc@syapse.com 
> <mailto:jjc@syapse.com>> wrote:
>
>>
>> I slept on Eric's question for several days .
>>
>> I ended up realizing that another aspect of the current drafts that I 
>> feel should change a bit is:
>>
>> https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html#rdf-datasets
>>
>> "When a graph name is used inside RDF triples in a dataset it may or 
>> may not refer to the graph it names. The semantics does not require, 
>> nor should RDF engines presume, without some external reason to do 
>> so, that graph names used in RDF triples refer to the graph they name."
>>
>> I would like some mechanism which indicates clearly that in my case 
>> it MAY refer to the graph it names, and I am proposing that
>>
>> <uuu> rdf:type rdfs:Graph
>>
>> be such a mechanism, and this be understood with intensional 
>> semantics like rdfs:Class rather than with extensional semantics like 
>> owl:Restriction
>>
>>
>> i.e. if in any graph in a dataset, there is such a triple, and we 
>> have an interpretation of that graph, and that the dataset does 
>> include a graph named <uuu> then it is pretty clear that the intent 
>> is that I am talking about the graph, and I would like the 
>> recommendations to say that in such interpretation it is this graph 
>> that we are talking about.
>>
>> Jeremy J Carroll
>> Principal Architect
>> Syapse, Inc.
>>
>>
>>
>> On Jul 19, 2013, at 9:06 PM, Eric Prud'hommeaux <eric@w3.org 
>> <mailto:eric@w3.org>> wrote:
>>
>>> On Jul 19, 2013 2:10 PM, "Jeremy J Carroll" <jjc@syapse.com 
>>> <mailto:jjc@syapse.com>> wrote:
>>> >
>>> > Sorry, I am failing to be brief ...
>>> >
>>> > On Jul 19, 2013, at 9:35 AM, Jeremy J Carroll <jjc@syapse.com 
>>> <mailto:jjc@syapse.com>> wrote:
>>> >
>>> >> [[[
>>> >>
>>> >> rdfs:Graph
>>> >>
>>> >> rdfs:Graph is the class of graphs. All instances 
>>> of rdfs:Graph correspond to the RDF model of a graph described in 
>>> the RDF Concepts specification [RDF-CONCEPTS].
>>> >> An instance of  rdfs:Graph MAY also be described in an RDF 
>>> dataset, in which case the triples in the graph SHOULD/MUST be the 
>>> triples as specified in the dataset.
>>> >>
>>> >> ]]]
>>> >>
>>> >>
>>> >> (I would be happy with either SHOULD or MUST)
>>> >
>>> >
>>> > looking again, MUST is too strong - since this would allow anyone 
>>> to modify anyone's else's intent. We need to qualify which RDF 
>>> datasets and reduce the MUST down to SHOULD.
>>> > e.g. "MAY also be described in a related RDF dataset, .. SHOULD 
>>> ." with the complete modified suggested text as
>>> >
>>> > [[[
>>> >
>>> > rdfs:Graph
>>> >
>>> > rdfs:Graph is the class of graphs. All instances 
>>> of rdfs:Graph correspond to the RDF model of a graph described in 
>>> the RDF Concepts specification [RDF-CONCEPTS].
>>> > An instance of  rdfs:Graph MAY also be described in a related RDF 
>>> dataset, in which case the triples in the graph SHOULD be the 
>>> triples as specified in the dataset.
>>> >
>>> > ]]]
>>>
>>> Sorry to be dim here, but does "the triples as specified in the 
>>> dataset" indicate a truth predicate of some sort (in which case I 
>>> would have expected "indicated" instead of "specified"). Or maybe 
>>> I'm misinterpreting a signal that another graph (probably the 
>>> default graph) includes all of the triples in the identified graph.
>>>
>>
>
Received on Friday, 26 July 2013 23:08:22 UTC

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