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Re: [Graphs] Proposal for Named Graph Semantics

From: Richard Cyganiak <richard@cyganiak.de>
Date: Fri, 8 Apr 2011 12:17:34 +0100
Cc: RDF WG <public-rdf-wg@w3.org>
Message-Id: <6B5022F1-A01F-40CD-89E0-F729945B0CAC@cyganiak.de>
To: Alex Hall <alexhall@revelytix.com>
Hi Alex,

Thanks once more, this is very helpful for understanding where you're coming from.

On 7 Apr 2011, at 21:56, Alex Hall wrote:
>> Why do you want a formal semantics?
> 
> In short, to help me sleep better at night.

:-)

>> How does it help addressing the multigraph use cases [1]?
> 
> Taking a quick look through that doc, I'll admit that for most of the use cases it doesn't address any issues that aren't addressed with the use of the abstract syntax.  There is, however, a section titled "Providing a standard foundation for the W3C specs" [2] and a sub-section on the alignment of Linked Data principles with RDF and AWWW which specifically states:
> 
> 'A formal definition of a concept such as "RDF Dataset", "Set of Named Graphs", and the g-box/g-snap/g-text distinction in a core RDF spec would make it easier to formally define such a model, tying together the Linked Data principles and practices, Architecture of the World Wide Web, and the REST model of information resources and representations, in a formal way.'
> 
> I make no claims that this proposal advances that goal in any particular way, I just highlight that section as an illustration that at least some people seem to want a more formal semantics.

It was me who wrote that use case.

I tried to get this onto the agenda of the WG at the workshop in Stanford:
http://www.w3.org/2001/sw/wiki/RDF_Core_Work_Items#Codify_the_follow-your-nose_approach_to_using_URIs_in_RDF

In the Future of RDF Standards survey, this work item got the second highest ranking of all (second to multigraphs):
http://www.w3.org/2002/09/wbs/1/rdf-2010/results#xg8

Nevertheless, the work item does not show up in the charter, except a note to the effect that something regarding linked data may be added to the Primer. I don't know how or why that decision was made.

Anyway, using multigraphs to codify the follow-your-nose approach is only *one* use case for multigraphs, and there are others that don't require and don't want to connect graphs to HTTP dereferenceability and web architecture. If we get just an abstract syntax out of this WG, then that would already be a great enabler for describing how RDF can work on the Web, together with AWWW and REST. So I don't really see a formal semantics for multigraphs as a requirement.

Best,
Richard
Received on Friday, 8 April 2011 12:15:18 GMT

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