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Re: owl:All(something) ??

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 14 May 2003 12:21:52 -0400
Message-Id: <p05200f54bae819786700@[]>
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: webont <www-webont-wg@w3.org>

At 10:14 AM +0100 5/12/03, Ian Horrocks wrote:

>As Jeremy points out, the various "same" relations are transitive, so
>there is no n^2 blowup in the number of property relationships
>required to express them, and the result is more compact than a (fully
>expanded) list would be.
>I also agree with Jeremy's account of the WG's thinking
>w.r.t. disjoint classes - that it is much less frequently required,
>and that the numbers (of classes) involved would typically be small
>(compared to unique individuals). It was therefore decided that
>additional syntax was not justified.
>W.r.t. disjoint properties, I'm not sure we even considered it. It is
>rarely asked for, and unlike the class/individual cases it is
>relatively difficult to express in the existing language given
>that we don't have property negation.

I had pretty much decided the above was correct, but yesterday I was 
talking to scientists about Semantic Web, and the following use case 
came up -- they want to be able to take biological taxonoma and 
represent in OWL, but they care very much what is and isn't disjoint 
(class wise).  In particular, they want to be able to have it be the 
case that at each level of the taxonomy the subclasses are disjoint 
-- i.e. they want to be able to say

AllDisjoint (Animal, plant, ...) 1s of classes

AllDisjoint (Mammalian, reptilian, amhibian ...)   (10s of classes)

and then
AllDisjoint (canine, feline, ovine, cervine, ceatacean ...) (100s of classes)

but not to assert that within canines there is disjointness between 
wolfes, dogs (of various types) etc, since these can interbreed etc. 
They said the bottom level would be in the 100s of classes, so could 
need 10000+ separate disjoint statements!

(Note that they used the animal example so I could understand, but 
they were actually talking about more subtle distinctions in 
proteomics and the like).

In short they had some compelling use cases in the same general area 
as Alan Rector's (scientific use of OWL in medicine/biology) and are 
purely at a class (not property) level, so maybe we need the syntax - 
esp. as it would be nearly the same syntax as for the alldifferent 

Note, in OWL full I would do this by simplying using the allDifferent 
on the classes - maybe that is the solution to suggest to these folks 
for now, although could mean a lot of scientistific applications 
would not be using DL...

Received on Wednesday, 14 May 2003 12:22:02 UTC

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