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RE: Classes and predicates as first class objects

From: <dmiles@users.sourceforge.net>
Date: Thu, 15 Aug 2002 11:09:48 -0700
To: <www-rdf-logic@w3.org>
Cc: <guha@guha.com>, "'Stephen Reed'" <reed@cyc.com>, "'Peter F. Patel-Schneider'" <pfps@research.bell-labs.com>
Message-ID: <000001c24486$f1b4a750$2fcce10c@logicmoo.com>

> > Hmm.  It appears to me that CycL does *not* treat
> predicates as first-class
> > objects,  In particular, the syntax for CycL at
> > http://www.cyc.com/cycl.html appears to disallow quantification over
> > predicates.

If part of the issue is the "Quantification",  It is implicit that the
axiom Steve mentioned ?PRED and ?GEN-PRED
are Universally quantified.  Existential quantification is further allowed
as well over predicates:


(forAll ?Event
   (implies
      (and
	  (isa ?Event HumanActivity)
	  (actors ?Event ?Someone)
	  (objectActedOn ?Event ?Something))
      (thereExists ?ActionPredicate
         (and
            (isa ?ActionPredicate ActionPredicate)
            (?ActionPredicate ?Someone ?Something)))))

Can be done as well (correct?)


> -----Original Message-----
> From: www-rdf-logic-request@w3.org
> [mailto:www-rdf-logic-request@w3.org]On Behalf Of Stephen Reed
> Sent: Thursday, August 15, 2002 10:06 AM
> To: Peter F. Patel-Schneider
> Cc: guha@guha.com; www-rdf-logic@w3.org
> Subject: Re: Classes and predicates as first class objects
>
>
>
> Although the cited documentation page does not contain an example of
> quantification over predicates in CycL, here is one:
>
> (implies
>        (and
>            (genlPreds ?PRED ?GENL-PRED)
>            (?PRED ?ARG1 ?ARG2))
>        (?GENL-PRED ?ARG1 ?ARG2))
>
> which Cyc paraphrases into English as:
>
> If ?PRED is a specialized form of ?GENL-PRED and PRED holds
> of some ARG1
> and some ARG2, then GENL-PRED holds of ARG1 and ARG2.
>
> Much more documentation on Cyc can be found at
> http://www.opencyc.org/doc
>
> -Steve
>
> On Thu, 15 Aug 2002, Peter F. Patel-Schneider wrote:
>
> >
> > From: "R.V.Guha" <guha@guha.com>
> > Subject: Classes and predicates as first class objects
> > Date: Wed, 14 Aug 2002 14:19:56 -0700
> >
> > [...]
> >
> > >  RDF, which has been largely influenced by the
> experimental "scruffy"
> > > side of AI has gone the route of many experimental AI
> systems (starting
> > > from KRL, RLL, .... CycL) and incorporated these as first
> class objects.
> >
> > [...]
> >
> > Hmm.  It appears to me that CycL does *not* treat
> predicates as first-class
> > objects,  In particular, the syntax for CycL at
> > http://www.cyc.com/cycl.html appears to disallow quantification over
> > predicates.
> >
> > peter
> >
> >
> >
>
> --
> ===========================================================
> Stephen L. Reed                  phone:  512.342.4036
> Cycorp, Suite 100                  fax:  512.342.4040
> 3721 Executive Center Drive      email:  reed@cyc.com
> Austin, TX 78731                   web:  http://www.cyc.com
>          download OpenCyc at http://www.opencyc.org
> ===========================================================
>
Received on Thursday, 15 August 2002 14:03:52 UTC

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