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Re: Comments on "SPARQL Query Language for RDF" (issues#SOURCE , UNSAID)

From: Dan Connolly <connolly@w3.org>
Date: Fri, 02 Sep 2005 08:23:04 -0500
To: Enrico Franconi <franconi@inf.unibz.it>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>, Sergio Tessaris <tessaris@inf.unibz.it>
Message-Id: <1125667385.16011.761.camel@dirk>

On Fri, 2005-09-02 at 04:27 +0200, Enrico Franconi wrote:
> As a first exercise, in [2] we already worked out the formal  
> semantics for core SPARQL and we also give some complexity result.
> We have a major concern on the possibility of giving any clear  
> semantics to the querying provenance part, which we probably would  
> prefer to leave out of the normative document.

This sounds like a request to re-open the SOURCE issue (and,
most likely, the UNSAID issue).

I note that the relevant design objective... 

  4.2 Data Integration and Aggregation

was adopted over the objection of Network Inference, and that
Klyne's Apr 2005 comment says "I think these should be removed
from the basic SPARQL core ...".

Also, we have a recent last call comment

"We would like to see 
a more formal definition of queries (and their results) 
in terms of RDF semantics"
 -- Barstow/Lassila 1 Sep 2005

to which I replied...

I suppose we could make explicit that for a query pattern P,
if S is a solution w.r.t. an input graph G,
then S(P) is entailed by G. Is that what you have in mind?

I think the idea can be expanded to cover UNION straightforwardly,
and perhaps OPTIONAL with some effort, but I don't know how this
applies to queries that use the GRAPH keyword.
 -- http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Sep/0008.html

So there does seem to be a non-trivial amount of new information
since our 2005-01-19 decision on the SOURCE issue.

On the other hand, to re-open it adds considerable risk to our schedule.

I'll consider for a while whether or not to re-open it. Advice is welcome.

> cheers
> --e.
> [1] <http://www.inf.unibz.it/krdb/w3c/sparql-notes-fub.pdf>
> [2] <http://www.inf.unibz.it/krdb/w3c/rdf-sparql-semantics.pdf>

Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Friday, 2 September 2005 13:23:12 UTC

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