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MS-6 D-Entailment and fixed datatype map

From: Birte Glimm <birte.glimm@uni-ulm.de>
Date: Tue, 4 Oct 2011 14:39:25 +0200
Message-ID: <CABt65OdTqWeQjqUr_Vhzpo9FAXYJ=QEJjbDaGo9Rx4h1fNWAKw@mail.gmail.com>
To: SPARQL Working Group <public-rdf-dawg@w3.org>
Hi all,
I am working through Michael Schneider's comments and I see two
possibilities to address
http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2011Jul/0013.html

The problem he identifies is that we call the D-entailment regime
D-entailment, but unlike the D-entailment specification in the RDF
model theoretic semantics document, we fix a datatype map. Thus, we
kind of change D-entailment, which is not our business.

There seem to be two solutions for this:
1) Change the name of the regime; Michael suggests XSD-entailment, but
since we also have rdf:PlainLiteral or rdf:XMLLiteral, I don't find
that very fitting, so we would have to find a better name.
2) We do not specify any concrete datatype map. In this case,
implementors would have to specify, e.g., in their system
documentation, what kind of datatypes they support. In this case, we
also have to think about canonicalisation. For all datatypes in the
regimes there is a wel-defined canonical form, which has to be used.
Otherwise, we again have the problem of infinite answers due to
infinitely many lexical forms for some data values. If we leave the
choice of the datatype map open, we might have to require that either
each datatype is such that a canonical form for each data value is
specified or, for datatypes where this is not the case, implementors
have to make sure that only finitely many answers are returned and
describe, e.g., in their system documentation, how that is achieved.

I tend to prefer option 1 as this is also less likely to require another LC.

Birte

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Received on Tuesday, 4 October 2011 12:39:56 GMT

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