W3C home > Mailing lists > Public > public-rdf-wg@w3.org > November 2011

Re: contexts, graph names and so on

From: Richard Cyganiak <richard@cyganiak.de>
Date: Thu, 10 Nov 2011 18:20:14 +0000
Cc: RDF-WG <public-rdf-wg@w3.org>
Message-Id: <37100DEB-85CE-44A9-A328-DD4A17F8BF81@cyganiak.de>
To: Andy Seaborne <andy.seaborne@epimorphics.com>

Summary: We're actually saying the same thing.

On 10 Nov 2011, at 14:51, Andy Seaborne wrote:
>> So you're saying:
>>    :g --???-->  X --denotes-->  graph
>> and there should be some way of stating what relation --???-->  is for a particular dataset.
>> Wouldn't it make more sense to say:
>>    :g --denotes-->  X --???-->  graph
>> because :g is an IRI and as such probably is supposed to denote something already. Then some obvious choices for --???-->  would be sameAs, hasRepresentation, and hasPrimaryTopic.
> It makes more sense (to me at least) to fix the second part as naming the the graph value.

It actually works out exactly the same. It's really like this (pardon the ASCII art):

  :g ----xxx----> {ggg}
   |                |
denotes          denotes
   |                |
   v                v
 thing ---yyy---> graph

The upper half of the picture is in the space of syntax, the lower half is in the space of values.

Starting at the graph IRI :g, your version goes right-then-down. The implicit X in this case is really a graph literal (it denotes the graph). Hence I write it as {ggg}.

Starting at the graph IRI :g, my version goes down-then-right. The implicit X in this case is really the thing that is actually denoted by the graph IRI. Hence I write it as “thing”.

Now, xxx and yyy are the same relationship – only that one is in syntax land, and one in value land. Xxx is a name for the relationship, and yyy is the actual relationship. Xxx denotes yyy.

If you think about the syntax of TriG files, then it makes sense to imagine some URI xxx between the <http://graphIRI> and the {graph literal}. If you think about the semantic relationship between the referent of <http://graphIRI> and the actual graph (set of triples), then that's yyy.

> I have an action to write some short use cases but these previosu messages do fit the model as I think of it:

Looking forward to the writeup.


> Subject: The "Rolling Snapshots" Pattern and Vocabulary
> http://lists.w3.org/Archives/Public/public-rdf-wg/2011Oct/0152.html
>  Sandro
> Subject: Time-varying g-boxes : a dataset pattern
> http://lists.w3.org/Archives/Public/public-rdf-wg/2011Oct/0148.html
>  Andy
> 	Andy
Received on Thursday, 10 November 2011 18:20:54 UTC

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