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A proposal to remove xsd:ENTITY, xsd:ID, and xsd:IDREF datatypes from OWL 2

From: Boris Motik <boris.motik@comlab.ox.ac.uk>
Date: Fri, 14 Nov 2008 08:38:09 -0000
To: "'W3C OWL Working Group'" <public-owl-wg@w3.org>
Message-ID: <E04FB98E2B03498AA0407DD83CED608F@wolf>

Hello,

Recently, Jos de Bruijn has made a comment that the xsd:ENTITY, xsd:ID, and xsd:IDREF datatypes are not recommended for use in RDF
and OWL 1. Therefore, he asked us why we included these datatypes into OWL 2. His original e-mail is here:

http://lists.w3.org/Archives/Public/public-owl-comments/2008Oct/0000.html

I looked into this and here are my findings. The xsd:ENTITY datatype has been derived from xsd:NCName by placing a rather strange
restriction on its value space:

	The value space of ENTITY is scoped to a specific instance document.

This probably means you cannot define the value space globally, but need to somehow associate it with the document where xsd:ENTITY
is being used. This is clearly quite complex and has not been intended in my original definition of the OWL 2 datatype map.

The xsd:ID and xsd:IDREF datatypes exhibit no such problems: their value space is exactly the same as for xsd:NCName. Therefore, I
am not really sure why RDF and OWL 1 warned against their usage.


Either, I believe that the simplest way to address Jos's comment is to delete all three datatypes from the rdf:text and OWL 2
specifications. Since neither of these datatypes provides us with something more than xsd:NCName, we are not really losing any
expressivity here.

Regards,

	Boris
Received on Friday, 14 November 2008 08:39:06 GMT

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