W3C home > Mailing lists > Public > public-rdf-wg@w3.org > May 2012

Re: Informative wording on identifiers for subgraphs

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 23 May 2012 13:41:32 -0500
Cc: Yves Raimond <Yves.Raimond@bbc.co.uk>, RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <DC556D7E-EA2D-47F5-A8A6-88676EF999C9@ihmc.us>
To: Richard Cyganiak <richard@cyganiak.de>
Richard, I am confused. 

Sometimes I get the sense that you want the graph names to refer not to graphs as such, but rather to 'stateful resources' (or whatever) which have a robust identity and emit graphs when poked, a REST-inspired kind of a thing.. (Cf. your responses on other threads.) At other times, however (as here) you seem to want the graph names to refer to an actual set of triples, a true Platonic RDF graph.

It really does matter which we choose, and I don't see how we can choose both (or not without a lot of new machinery to make the distinction, that we have not even discussed yet) and I don't think it is viable to just be muddled or ambiguous about it, as that is the muddle we are in already and are trying to get straight. 

For example, if the graph names refer to stateful resources, then there are two rather different ways to identify a subgraph or a larger graph. ONe is to speak of a subset (defined somehow) of the graph that is the current state of the stateful resource, the other is to have a relation between two resources such that one returns a subset of what the other returns, at any time. These behave differently and would need to be implemented differently. 

I have no axe to grind here. I would be quite happy if we were to declare that graph names in datasets always refer to stateful resources. I would also be happy if we decide they always refer to graphs. But I am not happy about it being ambiguous or undecided. I do feel that it is very important that we choose one story and stick to it. Which one do you want to pitch for?


On May 23, 2012, at 1:12 PM, Richard Cyganiak wrote:

> Hi Yves,
> I took an action to propose some informative wording regarding the possibility of identifying subgraphs of a larger graph. See below for a first attempt. I suppose this would go somewhere near the definition of “RDF dataset” or whatever we end up calling these things. The terminology (named graphs etc.) still may have to change of course. Is this wording ok for you?
> Best,
> Richard
> [[
> Note: Graphs in an RDF dataset may overlap. The same underlying set of triples may be divided up into named graphs along multiple dimensions (such as data owner or subject area) by repeating each triple in multiple graphs. Whether such a setup would be realized by storing each triple multiple times, or through views of some sort, is up to the implementation.
> ]]

IHMC                                     (850)434 8903 or (650)494 3973   
40 South Alcaniz St.           (850)202 4416   office
Pensacola                            (850)202 4440   fax
FL 32502                              (850)291 0667   mobile
phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
Received on Wednesday, 23 May 2012 18:42:11 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 17:04:18 UTC