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Re: ISSUE-124 (datarange complement): The complement of a datarange is defined relative to the whole data domain

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Tue, 06 May 2008 10:47:19 +0100
Message-ID: <48202927.6020805@hpl.hp.com>
To: Boris Motik <boris.motik@comlab.ox.ac.uk>
CC: "'OWL Working Group WG'" <public-owl-wg@w3.org>


> Unfortunately, this is a "feature" and not a bug. Complements of data ranges are included into OWL 2 mainly in order to provide
> everything that is needed for reasoning: during reasoning, all concepts involving datatypes must be put into conjunctive normal
> form, and this cannot be done unless we have data ranges. But then, the complement of data ranges *must* be defined w.r.t. the whole
> domain, and not just the datatype being complemented; otherwise, using ComplementOf in order to put constructs into negation normal
> form would be unsound.
> 
> Therefore, this is somewhat unfortunate, but we have to live with it, I'm afraid.
> 


I am assuming it is possible to express the intersection of the 
enclosing type with the complement - so that Michael's point is more 
about usability than expressability.

I suspect that usability is a 'value added' feature of good OWL tools 
.... and not an inherent feature of the language :)

Jeremy
Received on Tuesday, 6 May 2008 09:49:07 GMT

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