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[closed] Re: Case for Reinstatement of Qualified Cardinality Restrictions

From: Jim Hendler <hendler@cs.umd.edu>
Date: Tue, 17 Jun 2003 07:53:57 -0400
Message-Id: <p05200f09bb14b0b1c0f8@[10.0.1.2]>
To: Alan Rector <rector@cs.man.ac.uk>
Cc: public-webont-comments@w3.org

At 9:07 AM +0100 6/17/03, Alan Rector wrote:
>Jim
>
>As I said in the informal discussions.  I accept the practical 
>difficulties; this is probably the least bad short term solution.
>
>I would be very concerned if the postponement were prolonged. We are 
>unable to migrate key applications from DAML+OIL to OWL without 
>QCRs.  I am also reluctant to encourage my colleagues who want to 
>start working on Anatomy to use something which is obviously flawed 
>for their requirements and requires awkward work-arounds.
>
>
>In short, I accept the proposal, reluctantly, but urge the Committee 
>to make the postponement as brief as possible.  The longer the 
>delay, the greater the pain when the change is made.
>
>I will read the proposals carefully and comment in due course.
>
>As for QCRs not having been needed in Protege, I suspect this is due 
>to a combination of three factors a) It being being less of a 
>problem in a less expressive language with less inferential power so 
>that the defects in the work arounds are less apparent b)  the use 
>of alternatives such as PAL constraints which are not available in 
>OWL; c) just accepting that the only way to do it is to to create 
>multiple slots to carry the load.  We know from experience that this 
>solution scales badly and is difficult to understand once you add a 
>classifier.
>
>(BTW I  understand that Holger Knublauch at Stanford's 
>implementation of  an OWL plugin for Protege has made provisions in 
>the design for extension to QCRs when available.)
>
>Regards
>
>Alan


Alan- thanks again for raising this issue.  I, personally, will 
encourage people (and invite you as well) to work on the publication 
of a Note that explains QCRs and how they could be added to OWL once 
we get the current version out the door.  I appreciate your being so 
understanding of the complexity of the undertaking to develop this 
recommendation.
  -Jim H.

-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  *** 240-277-3388 (Cell)
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Received on Tuesday, 17 June 2003 07:54:04 GMT

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