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Re: Using named graphs to model PROV's Accounts

From: Timothy Lebo <lebot@rpi.edu>
Date: Wed, 12 Oct 2011 00:55:16 -0400
Cc: Andy Seaborne <andy.seaborne@epimorphics.com>, public-rdf-prov@w3.org
Message-Id: <33A101C1-868F-4F27-9DA4-FB6A6C553AB5@rpi.edu>
To: Sandro Hawke <sandro@w3.org>

On Oct 11, 2011, at 4:43 PM, Sandro Hawke wrote:

> On Tue, 2011-10-11 at 20:32 +0100, Andy Seaborne wrote:
>> 
>> On 11/10/11 19:11, Timothy Lebo wrote:
>>> rdf-prov,
>>> 
>>> In preparation for the RDF WG F2F this week, I wanted to provide some discussion on using named graphs to address some provenance modeling.
>>> 
>>> I have updated http://www.w3.org/2011/prov/wiki/Using_named_graphs_to_model_Accounts to reflect some feedback and extend the discussion on named graphs.
>>> 
>>> In particular, I discuss:
>>> 
>>> * reuse of the SPARQL Service Description vocabulary to describe named graphs.
>>> * Meta Named Graph pairs,
>>> * a simple application of these to create Cache Graphs
>>> * the importance of modeling the "location" of a graph to disambiguate many graphs with the same name.
>>> 
>>> These components are needed to model PROV's notion of Accounts, which permit different agents to assert different views of the same "event" (i.e., ProcessExecution). I hope to wrap up all of this into a final proposal by the end of the week.
>>> 
>>> Any suggestions or comments appreciated.
>> 
>> 
>> As a principle (of AWWW), one name can only refer to one thing.
>> 
>> "graph" here seems to refer to graph-a-location but also "graph the 
>> contents of the location".  But those are different things.
> 
> 
> I might be confused, but it looks to me like Tim is making the best of a
> bad situation:


Here, the "bad situation" is that "lazy namers" have reused the same sd:name for multiple g-boxes, violating the AWWW principle that Andy cited.

Is the answer as simple as, "stop being lazy!"? 
Which means nobody can have a g-box in their SPARQL endpoint named <http://www.w3.org/People/Berners-Lee/card> , since that's something somewhere else.


> he's trying to use the "name" in a name-graph pair to
> identify a graph/gbox, but he's recognizing that [ because we haven't
> adopted my Web Semantics for Datasets proposal :-) ] the scope of that
> binding is only a single dataset.

In my writeup, I used the term "location", not "dataset". 
But yes, I'm using the "location" of the g-box to provide the contextualizing scope required to name the g-box -- since it's sd:name is inadequate.


>  He's calling the dataset identifier
> the "location".     At least that's how I'm reading it.

Exactly. Is "dataset" defined somewhere in RDF-WG, or are does the group reuse the SPARQL definition?

Regards,
Tim Lebo
Received on Wednesday, 12 October 2011 04:55:54 GMT

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