W3C home > Mailing lists > Public > public-rdf-wg@w3.org > February 2013

Re: Problem with auto-generated fragment IDs for graph names

From: Ivan Herman <ivan@w3.org>
Date: Sun, 17 Feb 2013 16:13:54 -0500
Cc: RDF-WG <public-rdf-wg@w3.org>
Message-Id: <F991003F-B84F-424D-820A-6150101A97FD@w3.org>
To: Andy Seaborne <andy.seaborne@epimorphics.com>

On Feb 17, 2013, at 11:50 , Andy Seaborne <andy.seaborne@epimorphics.com> wrote:

> 
> 
> On 17/02/13 16:36, Ivan Herman wrote:
>> Manu,
>> 
>> the problem with what you propose is that, I believe, it breaks some
>> SPARQL usage patterns out there. As far as I remember the main
>> obstacle around the denote vs. non-denote was that SPARQL is
>> completely silent on this issue which essentially means that in
>> SPARQL there is no way of finding out whether it denotes or not
>> denotes. So... any proposal in this issue *does* reopen the
>> floodgates of discussion. And I do not think we should do that.
> 
> Sort of, sort of not.
> 
> In one place, SPARQL is not silent -- FROM NAMED, but that is not a critical feature IMO.  Otherwise it is pretty neutral, defining mechanism rather than architecture.
> 
> But even when DAWG was discussing this, the usage of label=location was already in use, so the DAWG/SPARQL discussions had that as input.
> 
> The neutrality then was the way to get agreement then ... :-)

Sounds/looks familiar:-)

> 
> I can image a proposal whereby
> 
> <g> {...} is label and
> <value> = {...} is denotes
> 
> but then at that point, we should considering real graph literals and that's beyond RDF 1.1

Ie, floodgates:-)

We do have a plan for a separate note on *possible* semantics for named graphs, afaik, and that could include some non-normative typing approaches that we did discuss. That may give some guidance for the community. But we should have our Rec track document in order first.

Ivan


> 
>> Also: I do not believe this is strongly related to your JSON-LD
>> pattern issue with blank nodes. Ie, I would prefer to stay focused on
>> that issue.
> 
> +1
> 
>> 
>> Ivan
>> 
>> 
>> 
>> 
>> On Feb 17, 2013, at 10:56 , Manu Sporny <msporny@digitalbazaar.com>
>> wrote:
>> 
>>> On 02/17/2013 08:15 AM, Ivan Herman wrote:
>>>> I do not think so. I actually do not have a strong opinion on
>>>> the bnodes-as-graph-labels issue. What I am uneasy about is that,
>>>> *if we use them*, they would represent a different semantics as
>>>> IRI-s which is my understanding of Pat's emails. That is all.
>>> 
>>> Can we fix this based on what the RDF WG suggested that we do for
>>> JSON-LD? By creating a special form of fragment identifier to deal
>>> with the situation? I realize that IRIs-as-graph-names can
>>> currently be used for both denoting a graph and
>>> naming-but-not-denoting a graph use cases. What if we do something
>>> like this:
>>> 
>>> In general, graph names denote the graph (both IRIs and Blank Node
>>> Identifiers).
>>> 
>>> If a developer wants to use an IRI that names-but-does-not-denote
>>> the graph, they can append a "special" fragment identifier (that
>>> is specifically called out in one of the RDF specs) to the IRI.
>>> Something like:
>>> 
>>> http://example.com/graphs/1#_:unnamed OR
>>> http://example.com/graphs/1#_graphname:123
>>> 
>>> We might even want to create a new class of non-IRI value to
>>> name-but-not-denote a graph:
>>> 
>>> _connotation:27392
>>> 
>>> It seems to me that the case where we name-but-do-not-denote a
>>> graph is more rare than the case where we want to denote a graph by
>>> its name. Can somebody point to the discussion where we decided
>>> that we can't do this? Or rather, who in this group would strongly
>>> oppose this general approach?
>>> 
>>> Like some of the others on this list, I'd also not prefer that
>>> graph names do anything other than denoting the graph. I don't want
>>> to revisit the issue to debate it to death again. A simple
>>> preference straw-poll at the next telecon might show us that this
>>> idea is/isn't worth pursuing.
>>> 
>>> -- manu
>>> 
>>> -- Manu Sporny (skype: msporny, twitter: manusporny, G+: +Manu
>>> Sporny) Founder/CEO - Digital Bazaar, Inc. blog: Aaron Swartz,
>>> PaySwarm, and Academic Journals
>>> http://manu.sporny.org/2013/payswarm-journals/
>>> 
>> 
>> 
>> ---- Ivan Herman, W3C Semantic Web Activity Lead Home:
>> http://www.w3.org/People/Ivan/ mobile: +31-641044153 FOAF:
>> http://www.ivan-herman.net/foaf.rdf
>> 
>> 
>> 
>> 
>> 
>> 
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Sunday, 17 February 2013 21:14:21 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:25:54 GMT