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Re: SPARQL 1.1 Entailment Regimes

From: Ivan Herman <ivan@w3.org>
Date: Thu, 9 Jun 2011 08:35:19 -0700
Cc: antoine.zimmermann@insa-lyon.fr, public-rdf-wg@w3.org
Message-Id: <A6F9F011-44A3-4BBE-853E-B71D7B76711E@w3.org>
To: Alex Hall <alexhall@revelytix.com>

On Jun 9, 2011, at 08:17 , Alex Hall wrote:

> On Thu, Jun 9, 2011 at 8:38 AM, Antoine Zimmermann <antoine.zimmermann@insa-lyon.fr> wrote:
> Le 09/06/2011 13:55, Richard Cyganiak a écrit :
> On 9 Jun 2011, at 11:11, Antoine Zimmermann wrote:
> Should we update D-entailment such that it necessary supports XSDs?
> (my answer: yes)
> I don't think so.  The 'D' in RDF D-entailment is a placeholder for any datatype map that an application wants to use.  SPARQL defines the datatypes that must be present in that map for implementations of SPARQL D-entailment, but I don't think we want to force that on all RDF implementations.
> Wouldn't that cause problems with OWL2, which doesn't support all XSD types (eg xsd:time I believe)?
> Hmm, interesting. So, strangely enough, the datatype maps for the OWL 2 RDF-Based Semantics entailment regime are not extensions of the datatype maps of the D-entailment regime in SPARQL 1.1 (as it is written now). This disserves to be pointed out to the SPARQL WG.
> ...and the datatype maps for OWL2 and SPARQL are both different from the XSD datatype map defined in RDF.  For those interested, I pulled all this together on a wiki page:
> http://www.w3.org/2011/rdf-wg/wiki/XSD_Datatypes
> A couple of questions arise from this:
> 1. Should RDF's XSD datatype map be expanded to include the new XSD 1.1 xsd:dateTimeStamp (referenced by OWL2)?
> 2. Should we reference the new XSD1.1 spec for RDF?

I think we should at least seriously consider both these options, to be in line with OWL (and also RIF, b.t.w., which refers to XSD1.1, too).

Caveat: XSD 1.1 is not yet a Rec. The reason why we could not close the RIF and the OWL working groups is that both standards refer to a non-recommendataion draft only and, whenever XSD 1.1 is a Rec, we will have to reissue an edited recommendation with the proper references. On the other hand, hopefully this will not be an issue for RDF.


> -Alex
> Note, however, that D-entailment (in SPARQL terms) does not support all XSD types either.
> -- 
> Antoine Zimmermann
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Ivan Herman, W3C Semantic Web Activity Lead
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Received on Thursday, 9 June 2011 15:32:46 UTC

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