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Re: Classes and predicates as first class objects

From: Deborah McGuinness <dlm@KSL.Stanford.EDU>
Date: Thu, 15 Aug 2002 21:28:42 -0700
Message-ID: <3D5C7F7A.FB404E50@ksl.stanford.edu>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: macgregor@ISI.EDU, www-rdf-logic@w3.org

"Peter F. Patel-Schneider" wrote:

> From: "Bob MacGregor" <macgregor@ISI.EDU>
> Subject: Re: Classes and predicates as first class objects
> Date: Thu, 15 Aug 2002 14:50:30 -0700
> > This discussion started not as a question about the merits of DLs, but
> > asked what you get when you sacrifice the ability to treat classes/predicates
> > as arguments to other predicates.  Slightly paraphrasing:
> >
> > > > > Clearly, not allowing this feature (classes and arc labels as
> > > > > first class objects) buys description logics something.
> >
> > Please correct me if I'm wrong, but my recollection is that CLASSIC allowed
> > second-order syntax, and in fact made some claims as to the utility of doing
> > so.  I my recollection is correct, then its not the case that we have to make this
> > particular sacrifice to achieve the "benefits" of a DL.  Rather, the trade-off
> > exists only for certain subclasses of DLs.
> >
> > - Bob
> I'm not aware of any second-order capabilities for CLASSIC.
> Some versions of CLASS had an extra-logical connection between a class and
> a related individual.

This was a fourth feature that I should have added to my list of CLASSIC features beyond
standard dls (the list was closed, rules, and test functions).
We introduced the notion of a meta individual with classes.
I used this in my markup work for pruning presentations in my thesis (I stored
information about what was interesting to print in context) and as the place to capture
markup  for our query language

> This allowed a back-door way of associating
> properties with classes, much as in one of the stances on classes as
> instances that I sent out to WebOnt a while ago.
> peter

 Deborah L. McGuinness
 Knowledge Systems Laboratory
 Gates Computer Science Building, 2A Room 241
 Stanford University, Stanford, CA 94305-9020
 email: dlm@ksl.stanford.edu
 URL: http://ksl.stanford.edu/people/dlm
 (voice) 650 723 9770    (stanford fax) 650 725 5850   (computer fax)  801 705 0941
Received on Friday, 16 August 2002 00:28:49 UTC

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