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Re: ISSUE-55 (owl:class)

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Sun, 2 Dec 2007 19:46:27 +0000
Message-Id: <22D90D85-EB33-48D8-B5E2-E46B07C0BFAC@comlab.ox.ac.uk>
Cc: OWL Working Group WG <public-owl-wg@w3.org>
To: Jim Hendler <hendler@cs.rpi.edu>
See the emails on this issue, in particular http://lists.w3.org/ 
Archives/Public/public-owl-wg/2007Nov/0263.html and http:// 
lists.w3.org/Archives/Public/public-owl-wg/2007Nov/0258.html, for an  
explanation of the significant and not fully understood technical  

IMHO, if it goes anywhere this should go in some UFD giving advice on  
"repairing" ontologies (see also ISSUE-56).


On 2 Dec 2007, at 18:27, Jim Hendler wrote:

> My request in raising the issue was that if we postponed it, we  
> needed a clear statement as to why the problem exists (and several  
> people have suggested adding the note that many reasoners change  
> rdfs:class to owl:class despite the semantic issue) -- saying "  
> introduces significant and not fully understood technical  
> difficulties" does not satisfy what I asked this issue to be  
> addressed for.  Again, in studies of ontologies out there, a great  
> many OWL Full ontologies become OWL DL with this change, I would  
> think that it would therefore be incumbent on this group to either  
> encourage those users to use owl:class (by explaining why they  
> should) or make it clear they can still work with OWL DL tools if  
> they don't, but there are certain techniical risks (which I must  
> admit I still don't understand)
>  So if we postpone this issue, which I'm okay with, it requires an  
> explanation - and that is where I think we (the OWL community) has  
> failed to date.   In fact, I've been suggesting to my students that  
> they use rdfs:class in many applications since OWL DL tools fix it,  
> and RDF-only tools don't reject it...  this is clearly wrong  
> semantically (Which I explain to the best of my limited ability)  
> but right from a practical point of view...
>   -JH
> On Dec 1, 2007, at 3:07 PM, Ian Horrocks wrote:
>> I'm tending to postpone this issue on the grounds that it  
>> introduces significant and not fully understood technical  
>> difficulties.
> "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 Sunday, 2 December 2007 19:46:45 UTC

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