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Re: Graphs and Being and Time

From: David Wood <david.wood@talis.com>
Date: Tue, 1 Mar 2011 14:48:45 -0500
Cc: RDF WG <public-rdf-wg@w3.org>
Message-Id: <E7FE1751-C9AA-403E-B2D2-08723C97DF98@talis.com>
To: <nathan@webr3.org>

On Mar 1, 2011, at 14:06, Nathan wrote:

> David Wood wrote:
>> On Mar 1, 2011, at 05:32, Nathan wrote:
>>> Nathan wrote:
>>>> David Wood wrote:
>>>>> On Feb 24, 2011, at 13:12, Pat Hayes wrote:
>>>>> 
>>>>>> It is much simpler: it is just wanting the WG to acknowledge that "an RDF graph" can either be a mathematical set, or it can be some kind of document or data structure or file than can be transmitted over a computer network. But it can't be both.
>>>>> What is the difference between an "RDF graph" and a RESTful "resource"?  What is the difference between an "RDF graph token" and a RESTful "representation"?
>>>> REST maps a resource to a set of values over time, each single value has a 1:N relationship with representations, "RDF Graph" (the mathematical set, platonic abstraction, g-snap) equates to a single value, and "RDF Graph Token" equates to a representation of that single value.
>>> REST maps a resource to a set of values over time, each single value is a representation, representation equates to "RDF Graph Token" (a chunk of rdf/xml or turtle, a g-text in Sandro's mail).
>>> 
>>> The g-snap, or abstract graph, isn't a concept which relates to any REST concept, rather it is something specific to our RDF use-cases, in that we have a platonic abstraction, a mathematical set of triples, which we juggle different realizations of (from in memory structures through to serializations and so forth).
>>> 
>>> So, to re-answer your question, "RDF Graph" is a term we've used to refer to both the abstract set of triples, and the realizations of. The only thing which equates anywhere near a "RESTful resource" in our communities are "Named Graphs" and of course linked data which uses RESTful resources, we GET <u> to retrieve a realization of an abstract set of triples, to get some RDF in some format.
>> Pardon me for saying so, but that doesn't make sense to me.
>> A RESTful resource may be anything:  "the intended *conceptual* target of a hypertext reference" was one way Roy Fielding put it (emphasis mine).  There is no reason I can see that an abstract, mathematical concept cannot be a RESTful resource.
> 
> I don't really want to drag this subject up on this list, unless the chairs / team contacts think it's worth it. So I'll merely point to a discussion on this:
>  http://lists.w3.org/Archives/Public/public-awwsw/2011Mar/0002.html
> do also see the replies which clarifies the two world views of IRs, and the third world view of no IRs just anythings.


OK, I'll let it go.  Perhaps we can find some time at the ftf to discuss this in person.  I still disagree, even having read the thread.

Regards,
Dave



> 
>> Andy neatly ducked the question of mapping to a resource:
>> On Mar 1, 2011, at 06:30, Andy Seaborne wrote:
>>> g-box - place holding a sequence-over-time of values
>>> g-snap - one such value
>>> g-text - the REST representation.
>> Instead, I suggest something like this:
>> g-box - a REST resource, over time.
>> g-snap - a conception of the REST resource at the time it is addressed.
>> g-text - the REST representation.
> 
> in which case I'd suggest just g-box and g-text, as g-snap is definitely an RDF concept, whether it helps to mention it I don't know (Pat? judging by his last reply I assume not) - if g-snap is needed, then there may be some guidance coming up later in the year early next year from the TAG on such subjects and whether that does correlate to "the conception of the REST resource at the time it is addressed", or at least clarifying documents via the AWWSW TF (a tag task force) that show the world views.
> 
> Best,
> 
> Nathan
Received on Tuesday, 1 March 2011 19:49:20 UTC

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