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Re: Range interpretation question.

From: Jeen Broekstra <jbroeks@cs.vu.nl>
Date: Thu, 26 Apr 2001 09:45:54 +0200 (CEST)
To: Ken Baclawski <kenb@ccs.neu.edu>, <www-rdf-logic@w3.org>
cc: Arjohn Kampman <akam@aidministrator.nl>, <conen@gmx.de>
Message-ID: <Pine.GSO.4.32.0104260935480.15708-100000@flits.cs.vu.nl>
On Wed, 25 Apr 2001, Ken Baclawski wrote:

> On Wed, 25 Apr 2001, Arjohn Kampman wrote:
>
> > Assume that the C is rdfs:Literal and that you're using
> > a resource uri as a target of the property. Using (b)
> > this would mean that the uri is a literal. To the best
> > of my knowledge, a uri cannot be both a resource and a
> > literal.
>
> No, the DAML+OIL axiomatic semantics states that literals
> are resources.  From Axiom 17:
>
> Ax17.    (=> (Type ?r ?c) (and (Type ?r Resource) (Type ?c rdfs:Class)))
>
> one can conclude (by setting ?c to rdfs:Literal) that
>
> (=> (Type ?r rdfs:Literal) (Type ?r Resource))

Maybe I misunderstand, but my impression is that this axiom
does not hold for Literal, because membership of the set of
literals is not expressed using an explicit type
relationship.

If it _is_ to interpreted as you say, then there is a
strange discrepancy here between RDFS (in which Literals and
Resources are disjoint sets) and DAML+OIL.

Regards,

Jeen
-- 
                               Vrije Universiteit, Faculty of Sciences
Jeen Broekstra              Division of Mathematics & Computer Science
jbroeks@cs.vu.nl                                    de Boelelaan 1081a
http://www.cs.vu.nl/~jbroeks        1081 HV Amsterdam, the Netherlands
Received on Thursday, 26 April 2001 03:50:12 GMT

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