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Re: DAML: restricting number of elements in a list

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Thu, 28 Feb 2002 12:44:13 +0000
Message-ID: <15486.9757.987988.55755@cs.man.ac.uk>
To: Steven Gollery <sgollery@cadrc.calpoly.edu>
Cc: www-rdf-logic@w3.org
On February 12, Steven Gollery writes:
> Ian,
> 
> Are you saying that the use of List is restricted to defining DAML itself? Or is it legal for an
> ontology to define a property whose range is daml:List? (I understand now that the items in a
> List are unordered, I just want to find out whether I can use List in my own definitions or not.)

It is not illegal, but DAML+OIL doesn't give any (special) semantics
to it. You can of course define your own lists class using DAML+OIL
and use that as a restriction - in that case you would get the
semantics you expect (i.e., those associated with your definition of
lists).

Ian

> 
> Steven
> 
> Ian Horrocks wrote:
> 
> > On February 11, Steven Gollery writes:
> > > >
> > > > Ian,
> > > >
> > > > It seems to me that the concept of "order" is fundamental in describing
> > > > elements of many ontologies. Why was the decision made not to include this in
> > > > DAML?
> > > >
> > > > Steven Gollery
> > > >
> > >
> > > Obviously, this is an overstatement. It is perfectly possible to define the equivalent of a
> > > linked list, as DAML-S does in its "nextProcessComponent" property, which provides a notion
> > > of "order". What I was really wondering here is: why was the decision made that a daml:list
> > > would be unordered?
> >
> > daml:list is part of the syntax of the language and is used to
> > represent sets of classes, e.g., in a conjunction. As you know, sets
> > are not ordered.
> >
> > Ian
> >
Received on Thursday, 28 February 2002 07:45:24 GMT

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