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Re: Actions 211 and 212: proposed changes to the extensions of basic graph pattern matching

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Mon, 19 Apr 2010 11:46:43 +0100
Message-ID: <z2i492f2b0b1004190346k2f1eb1f3z67eeb0d5071dfc22@mail.gmail.com>
To: SPARQL Working Group <public-rdf-dawg@w3.org>
Cc: Andy Seaborne <andy.seaborne@talis.com>
Hi all,
following up on the proposed changes to the extensions of BGP
matching, I would suggest the following. The first condition is
changed from
1 -- The scoping graph, SG, corresponding to any consistent active
      graph AG is uniquely specified and is E-equivalent to AG.
to
1 -- The scoping graph, SG, corresponding to any consistent active
      graph AG is specified uniquely up to RDF graph equivalence and is
      E-equivalent to AG.
Then we have made it explicit that differences in bnode labels only are ok.

The second change regarding finiteness is more tricky. I'll try what
Andy suggested, which leaves it to the entailment regimes to identify
appropriate conditions and suggest to change from
4 -- Each SPARQL extension must provide conditions on answer sets
     which guarantee that every BGP and AG has a finite set of answers
     which is unique up to RDF graph equivalence.
to
4 -- Each SPARQL extension MUST provide conditions, which guarantee
     that the answer set for every BGP and AG is uniquely specified up to
     RDF graph equivalence, and SHOULD provide further conditions to
     prevent trivial infinite answers as appropriate to the regime.

Maybe we can discuss and hopefully agree on that in tomorrow's teleconf.
Cheers,
Birte


-- 
Dr. Birte Glimm, Room 306
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Received on Monday, 19 April 2010 10:47:21 GMT

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