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Re: Missing AllDisjoint?

From: Dan Connolly <connolly@w3.org>
Date: 19 Jun 2003 09:41:51 -0500
To: "Richard H. McCullough" <rhm@cdepot.net>, wwmm <wwmm@seu.edu.cn>, Bernard Vatant <bernard.vatant@mondeca.com>
Cc: public-webont-comments@w3.org
Message-Id: <1056033711.8943.558.camel@dirk.dm93.org>

Thanks for taking the time to comment on the spec;
sorry for the delay in responding...

> > > Envoyé : lundi 12 mai 2003 04:13
> > > Since there is an owl:AllDifferent, why is there not an
> > > owl:AllDisjoint?

In section 5.3. Disjoint Classes in the Guide, you can see
an explanation of the topic...

  The  A common requirement is to define a class as the union of
  a set of mutually disjoint subclasses. 

  -- http://www.w3.org/TR/owl-guide/#DisjointClasses

it goes on to explain the details of exactly how to do it.

> From: "Bernard Vatant" <bernard.vatant@mondeca.com>
> To: "wwmm" <wwmm@seu.edu.cn>; <public-webont-comments@w3.org>
> Sent: Wednesday, May 14, 2003 8:56 AM
> Subject: RE: Missing AllDisjoint?
> >
> > I've not seen any answer to this question, or maybe I missed it, but I
> > agree that having AllDisjoint would be very useful, since partition is a
> > frequent situation, very heavy to deal with using n^2 DisjointWith ...

On Wed, 2003-05-14 at 14:56, Richard H. McCullough wrote: 
> A more useful implementation of this capability would be a
>     property superClassOf
> with
>     domain Class
>     range List
> where
>     subclasses in List are disjoint, distinct and exhaustive.


A special language construct for this is the subject of
issue 5.21 drop disjointUnionOf
http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I5.21-drop-disjointUnionOf

We decided, 24 Oct 2002, to drop the special construct because...

  The only thing going for owl:disjointUnionOf is that it uses
  fewer triples than the alternative. However almost all disjoint
  unions are small so the number of owl:disjointWith triples will not
  be that large. [...] 

Unless we have new information, information that the working
group didn't have at the time we made our decision, we prefer not to
re-open issues. The points you raise in your commenst are a good
ones, but they don't seem to be new.

Please let us know if you find the explanation in the Guide
and the rationale for the decision not to adopt a special
construct satisfactory.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 19 June 2003 10:41:31 GMT

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