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Re: LANG: compliance levels

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Thu, 2 May 2002 09:12:47 +0100
Message-ID: <15568.62719.51156.196992@merlin.oaklands.net>
To: "Jonathan Borden" <jonathan@openhealth.org>
Cc: "Enrico Motta" <e.motta@open.ac.uk>, "Deborah McGuinness" <dlm@ksl.stanford.edu>, <www-webont-wg@w3.org>
On May 2, Jonathan Borden writes:
> Ian Horrocks wrote:
> >
> > I would suggest that where universal quantification is being widely
> > used in practice, it is either as a result of its being the only
> > available option and/or the fact that many users assume an implicit
> > existential - it never occurs to them that people all of whose
> > children are doctors may not have any children at all (I would hardly
> > bother telling you what type their children must be if they don't have
> > any children, would I?).
> >
> 
> Hmm. What about combining toClass with minCardinality, so that there would
> have to be, e.g., at least one child, and that child would have to be a
> doctor -- or would that just be a minCardinalityQ?

No. As I think Deb already pointed out, asserting (minCardinality 1 P)
along with (toClass P C) means that there can never by any Ps that
are not Cs. Saying (minCardinalityQ 1 P C) means that there is at
least one P that is a C, but says nothing about the existence or
otherwise of other Ps that are not Cs. So, (minCardinalityQ P 1 C) is
equivalent to (hasClass P C). As I mentioned at one of the earlier F2F
meetings, the Q restrictions are the most general and can capture both
hasClass and toClass: (maxCardinalityQ 0 P (not C)) is equivalent to
(toClass P C).

Ian

> 
> Jonathan
Received on Thursday, 2 May 2002 04:16:01 GMT

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