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Re: basic decisions underlying DAML-ONT (defined classes)

From: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
Date: Sun, 15 Oct 2000 00:31:38 +0000
Message-ID: <39E9170A.F2CF300D@cs.vu.nl>
CC: www-rdf-logic@w3.org
"Peter F. Patel-Schneider" wrote:
> > >
> > > Why not create a new kind of object, perhaps called a description, which
> > > would ``contain'' restrictions and qualifications.   The meaning of a
> > > description would be the intersection of these restrictions and
> > > qualifications.  A class could then be defined as ``equivalentTo'' to a
> > > description.

From: Dan Connolly <connolly@w3.org>
> > Yes, that's the basic idea. It's called reification
> > in the RDF specs; it's called quoting elsewhere.

"Peter F. Patel-Schneider" wrote:
> I don't think that I am asking for reification or quoting, just something like:
> [... Details of Peter's proposal deleted, FvH]

Maybe I'm missing something here, but can this not already be done in current DAML?
The crucial point is in the following qoute from an earlier off-line email exchange with Dan:
(excuse the now obsolete list-syntax):

> In DAML, equivalent isn't a relation between two
> class *names*, but between two *classes*. So of course we can say:
>
>  <Class ID="human">
>    <equivalentTo>
>      <Class>
>        <UnionOf parseType="daml:collection">
>          <Class about="#Man"/>
>          <Class about="#Woman"/>
>        </UnionOf>
>      </Class>
>    </equivalentTo>
>  </Class>

[a] This does give you defined classes, doesn't it?
    (it gives nec. & suff. conditions for the class "human")
[b] This also shows that DAML-ONT's is not similar to SHOE's <DEF-RENAME> element,
as Jeff Heflin suggested, since <DEF-RENAME> is a syntactic operation concerning class names, not a relation between two classes?

Frank van Harmelen.
                 ----
Frank.van.Harmelen@cs.vu.nl              http://www.cs.vu.nl/~frankh
Department of AI, Faculty of Sciences,  Vrije Universiteit Amsterdam
de Boelelaan 1081a, 1081HV Amsterdam, The Netherlands
tel (+31)-20-444 7731 fax&voicemail (+31)-20-8722806
Received on Saturday, 14 October 2000 19:30:07 GMT

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