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Re: Agenda requests: Issues we can decide?

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Wed, 7 Nov 2007 08:25:38 -0500
Message-Id: <D8B0214F-E779-4F68-A0A5-102DECEB0B06@cs.rpi.edu>
Cc: bparsia@cs.man.ac.uk, public-owl-wg@w3.org
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>

What would be the problem with having an allDisjoint that was  
identical in form to the AllDifferent construct?  The issue is that  
you need N^^2 Disjoint statements for N classes - and if these don't  
form a disjointUnion (which is often the case in the real world, as  
we may not know all members of the class in advance) you're hosed.   
The WOWG felt this was a good construct, but that it was brought up  
too late in the game (after LC) and that checking the Model Theory to  
make sure there were no bugs was a problem with time.  We now have  
that time, and it seems to me it is a no brainer to add this.  There  
was actually considerable consensus in the WG that this would be a  
good feature to add, but as chair I decided to go with the opinion  
that we didn't want to hold up the language to add it and thus I  
talked a couple of people out of objecting and we left it on the  
issues list.  I've already seen a couple of OWL implementations add  
it, and can't understand why we wouldn't include it.
  I didn't realize allDifferent is not included in 1.1 (if I  
understand Peter's email below), in which case let's fix that also


On Nov 7, 2007, at 3:59 AM, Peter F. Patel-Schneider wrote:

> From: Bijan Parsia <bparsia@cs.man.ac.uk>
> Subject: Re: Agenda requests: Issues we can decide?
> Date: Tue, 6 Nov 2007 22:14:26 +0000
>
>>
>> On Nov 6, 2007, at 9:40 PM, Jim Hendler wrote:
>>
>>> Bijan, can you let us know your reasons for these, esp number 8- if
>>> we can do keys, couldnt we do this by same mechanism?
>
>> sure
>>>> http://www.w3.org/2007/OWL/tracker/issues/2 (easy yes)
>>
>> AllDisjoint not being in the RDF mapping seems pretty clearly a bug.
>> What's the advantage of syntatic sugar that doesn't appear in the
>> only canonical exchange syntax?
>
> The status of owl:allDisjoint goes back to a decision by the WebOnt  
> WG.
> There was quite a bit of discussion related to the matter,  
> including the
> threads starting at:
>
> http://lists.w3.org/Archives/Public/www-webont-wg/2003Sep/0218.html
> http://lists.w3.org/Archives/Public/www-webont-wg/2002Oct/0120.html
>
> I expect that there are also earlier threads as well.
>
> There are also the following issue and piece of the Guide:
>
> http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I5.21-drop- 
> disjointUnionOf
> http://www.w3.org/TR/owl-guide/#DisjointClasses
>
> Remember that RDF doesn't have syntactic sugar, so you can't exactly
> argue from the "missing syntactic sugar" viewpoint.
>
> [...]
>
>> Hope this helps.
>>
>> Cheers,
>> Bijan.
>
> If we are looking for easy yesses in the RDF mapping then we should  
> fix
> the bug that the OWL 1.1 mapping doesn't allow the OWL 1.0 mapping to
> owl:AllDifferent.  This is a counterexample to the claim that all OWL
> 1.0 ontologies in RDF form are also OWL 1.1 ontologies in RDF  
> form.  (I
> had though that ISSUE-2 was this one until now.)
>
> peter

"If we knew what we were doing, it wouldn't be called research, would  
it?." - Albert Einstein

Prof James Hendler				http://www.cs.rpi.edu/~hendler
Tetherless World Constellation Chair
Computer Science Dept
Rensselaer Polytechnic Institute, Troy NY 12180
Received on Wednesday, 7 November 2007 13:26:11 GMT

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