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Re: DAML: restricting number of elements in a list

From: Ken Baclawski <kenb@ccs.neu.edu>
Date: Mon, 11 Feb 2002 00:46:44 -0500 (EST)
To: Ian Horrocks <horrocks@cs.man.ac.uk>
cc: Steven Gollery <sgollery@cadrc.calpoly.edu>, www-rdf-logic@w3.org
Message-ID: <Pine.LNX.3.96.1020211002724.30309B-100000@steam>
On Sat, 9 Feb 2002, Ian Horrocks wrote:

> On February 7, Ken Baclawski writes:
> > The daml:item property relates a list to each of its elements.  One can
> > impose a daml:minCardinality restriction on the daml:item property to
> > ensure that the number of vertices in a polygon is at least 3. 
> > 
> > Ken Baclawski
> > Ken@Baclawski.com
> > UBOT Project
> 
> I am afraid that this is a common misconception. You can write such a
> thing, but if you read the language specification you will find that
> daml+oil does not provide any semantics for it, so it does not have
> the effect that you desire (in fact, from the point of view of
> daml+oil, it has no effect whatsoever). 

You are correct that the intention of daml:collection is to be unordered,
but the axiomatic semantics specifies that DAML lists do have an order,
via the daml:first and daml:rest properties.  Furthermore, the axiomatic
semantics specifies that daml:item relates a list to each item in the list
(item-axiom-2).  Which one specifies the semantics of DAML+OIL:  the
axiomatic semantics (written in KIF) or the language specification
(written in English prose)? 

Ken Baclawski
Ken@Baclawski.com
UBOT Project
Received on Monday, 11 February 2002 00:46:55 GMT

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