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

From: Ivan Herman <ivan@w3.org>
Date: Sun, 17 Feb 2013 11:36:37 -0500
Cc: RDF WG <public-rdf-wg@w3.org>, Linked JSON <public-linked-json@w3.org>
Message-Id: <21F4AF26-3C1B-447F-A628-F3473CD20915@w3.org>
To: Manu Sporny <msporny@digitalbazaar.com>
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.

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.

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
Received on Sunday, 17 February 2013 16:37:05 GMT

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