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

From: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
Date: Mon, 18 Apr 2011 20:52:42 +0200
Message-ID: <4DAC887A.4030705@liris.cnrs.fr>
To: Pat Hayes <phayes@ihmc.us>
CC: "public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
<snip/>

On 04/18/2011 07:58 PM, Pat Hayes wrote:
> 
> On Apr 18, 2011, at 9:47 AM, Pierre-Antoine Champin wrote:
>> Well, HTTP explicitly states that a URI identifies a resource [1], and
>> then gives semantics to the status codes one obtains when sending HTTP
>> requests to the given URI.
> 
> But it is (notoriously) unclear what exactly that word 'identifies'
> means, and several prominent Web gurus are on record with the view that
> whatever it means, it most certainly is not synonymous with 'refers to'
> or 'denotes' as used by semantic specifications. So it is still up to us
> to declare what specifies the 'URI is the name of graph' relationship,
> and how it relates to http.

I guess I need to dig a little deeper on http-range-14, then...

>> I like to think of 'identification' in HTTP as a subset of
>> 'identification' in RDF, more precisely as the restriction of this
>> relation to "information resources" [3].
> 
> The word "identification' is not used anywhere in the RDF specs, I believe. 

rephrase: I like to think that any information resource identified (as
per HTTP) by a URI is also denoted (as per RDF) by that URI.

>>
>> So if I read
>>
>>  <uri1> a :G-box .
>>
>> and then, by fetching <uri1>, I get a "200 Ok" and a Turtle
>> representation (a g-text), then I would tend to consider that <uri1> the
>> g-box "contains" the triples that I parse from the g-text.
> 
> That is the http-range-14 decision in a nutshell. However, what if
> you get a 303 redirect? What if you get a 404? What if the IRI has a hash in
> it somewhere?

Then all I can tell is that the resources is not reachable through HTTP,
and I need other means to know more about it -- possibly more RDF about
that resource.

> I am not meaning to imply that there are no answers to
> these questions, only that we need to provide them.

I would be happy with the one above.

  pa
Received on Monday, 18 April 2011 18:53:11 GMT

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