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Re: owl:All(something) ??

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 12 May 2003 07:37:35 -0400 (EDT)
Message-Id: <20030512.073735.125118428.pfps@research.bell-labs.com>
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org

From: Jim Hendler <hendler@cs.umd.edu>
Subject: owl:All(something) ??
Date: Sun, 11 May 2003 22:36:40 -0400

> We have received a couple of comments that we should have some other 
> constructs similar to allDifferent
>   one comment suggest AllSame
> another asks for AllDisjoint
> 
> we need an answer as to why we included the first and not the latter 
> two, or we need to decide our current mechanism could be extended to 
> allow it to be used on other properties  (which would probably not 
> require another LC if we make it clear this is just a piece of 
> syntactic sugar since we have the appropriate semantics already).
> 
> Any thoughts?

One problem with this line of thinking is that we do not have the
appropriate semantics already.  Every change to the syntactic constructs of
OWL requires a change to the underlying semantics for OWL, because each
such construct also has to exist in interpretations and have its own
special semantic constraints.  Each construct must have its own
section in all the correspondence proofs, as well.  Changes to the
syntax of OWL cannot simply be syntactic sugar.

The reason that AllDifferent was added to OWL was to provide a mechanism to
easily handle a local unique-names-assertion, which would otherwise take
O(n^2) differentIndividuals assertions.  No similar case can be made for
the other constructs.

If, however, it is deemed more important to be consistent in whether such
constructs are permitted it would be better, in my view, to remove
AllDifferent.

Peter F. Patel-Schneider
Bell Labs Research
Lucent Technologies
Received on Monday, 12 May 2003 07:37:45 GMT

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