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Re: Fwd: Case for Reinstatement of Qualified Cardinality Restrictions

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Thu, 17 Apr 2003 13:42:25 +0100
Message-ID: <16030.41265.541086.197282@galahad.cs.man.ac.uk>
To: Dan Connolly <connolly@w3.org>
Cc: Jim Hendler <hendler@cs.umd.edu>, webont <www-webont-wg@w3.org>

First off I would like to point out that although Alan works in the
same department as me, his comments are completely independent and
nothing to do with me (honest!).

Having said that, no one will be surprised to hear that I support the
proposal to re-instate QNRs: we had them in OIL and D+O, and I argued
for their retention in OWL. The argument was weakened by a lack of
convincing ontological use cases at that time. Now that people have
been working with D+O for a while, and have built some significant
ontologies using it, convincing use cases do seem to have arisen.


On April 16, Dan Connolly writes:
> On Wed, 2003-04-16 at 13:44, Jim Hendler wrote:
> > The following long message (from [1]) comes from Alan Rector to our 
> > comments list, addressing the issue of the qualified constraints - 
> > basically, he's asking us to reopen issue 3.2 Qualified Cardinality 
> > constraints.  Guus and I would like to hear the WG's feelings on 
> > this.  Since there's no specific document addressed (although it 
> > would require changes in every document), Guus and I will handle this 
> > email and its response.
> >   -JH
> > [1] 
> > http://lists.w3.org/Archives/Public/public-webont-comments/2003Apr/0040.html
> Just as we encourage editors to reply to issues about specs
> by quoting spec text, I encourage you to reply regarding
> decisions made by the WG by quoting from the decision records.
> i.e. from
> http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I3.2-Qualified-Restrictions
> Feel free to edit the issues list to make it a better summary
> of the WG proceedings (though of course we don't want to
> rewrite history).
> In the issues list we find a nicely edited rendition of
> Jeremy's proposal to close, which I might expect to find
> under "resolution" rather than under
> the issue description. The "resolution" field cites the 25 Apr minutes,
> which is good... and yes, the minutes just say that Jeremy's proposal
> of 19Apr was accepted.
> So while it's probably OK as is, I encourage you to take this
> opportunity to move some of the issue description under the "resolution"
> field in the issues list.
> Maybe I'll just do it... ok, done.
>   $Revision: 1.53 $ of $Date: 2003/04/16 20:56:46 $
> I edited the markup of the issues list to be XML well-formed while
> I was at it.
> Oh bother... now that I go and read what he wrote, I see that
> he's well aware of our decision record and it doesn't satisfy
> him.
> His argument to reopen the issue seems quite compelling.
> I'm convinced.
> > >V) "There are no compelling use cases."  To the contrary.  Where 
> > >cardinality restrictions are required, we have found that it is 
> > >almost always qualified cardinality restrictions rather than 
> > >unqualified restrictions which are required.  Consider the following 
> > >use cases/examples, all of which have arisen in the development of 
> > >real ontologies for real applications:
> > >
> > >a)    Anatomy:  "The normal hand has exactly five fingers of which 
> > >one is a thumb"  (It has many other subdivisions
> > >including the palm, back of the hand, thenar region, etc.so an 
> > >unqualified restriction on the property has-subdivision
> > >does not capture the meaning. (innumerable similar examples, e.g. 
> > >"The heart has four chambers two atria and two
> > >ventricles", etc.  The number of cases in anatomy is legion.
> > >
> > >b)  Bio-ontologies and chemistry: i) "Tricarboxylic acid contains 
> > >exactly three carboxyl groups" - but also an acidic
> > >group.  "GPCRs have exactly seven trans-membrane alpha-helixes" (but 
> > >many other subunits which distinguish one
> > >GPCR from another).  (GPCRs are an important class of receptor 
> > >proteins in cellular control and the subject of virtually an
> > >entire sub-discpline of molecular biology.) "Haemoglobin consists of 
> > >four subunits each of which contains exactly one haem group each of 
> > >which contains exactly one iron ion" - each subunit consists of 
> > >numerous other groups besides the haeme group and contains many 
> > >other ions.
> [...]
> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 17 April 2003 08:34:51 UTC

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