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Re: owl:Thing in RL profile?

From: Markus Krötzsch <mak@aifb.uni-karlsruhe.de>
Date: Thu, 13 Aug 2009 14:18:38 +0200
To: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Cc: Michael Schneider <schneid@fzi.de>, "Boris Motik" <boris.motik@comlab.ox.ac.uk>, "W3C OWL Working Group" <public-owl-wg@w3.org>
Message-Id: <200908131418.39113.mak@aifb.uni-karlsruhe.de>
Thanks for all the answers. This makes sense. I did not think about the impact 
that this feature would have when used in entailed ontologies. Classifying 
something as owl:Thing in the *premise* ontology seemed harmless enough.

Cheers,

Markus

On Donnerstag, 13. August 2009, Ian Horrocks wrote:
> I agree. Making changes here is non-trivial, and shouldn't be
> attempted at this stage.
>
> Ian
>
> On 13 Aug 2009, at 10:51, Michael Schneider wrote:
> > The current situation is that starting from explicit typing triples
> >
> >   ex:C rdf:type owl:Class .
> >   ex:w rdf:type ex:C .
> >
> > the RL/RDF rules provide
> >
> >   ex:C rdfs:subClassOf owl:Thing . // via rule scm-cls
> >   ex:w rdf:type owl:Thing .        // via rule cax-sco
> >
> > But this does not follow without explicit typing.
> >
> > There are actually several RL rules treating owl:Thing and
> > owl:Nothing, but
> > it's pretty incomplete support. But trying to change anything in
> > this late
> > stage (after PR-voting!) would probably be a bit risky... :-)
> >
> > Michael
> >
> >> -----Original Message-----
> >> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-
> >> request@w3.org]
> >> On Behalf Of Ian Horrocks
> >> Sent: Thursday, August 13, 2009 11:32 AM
> >> To: Boris Motik
> >> Cc: 'W3C OWL Working Group'
> >> Subject: Re: owl:Thing in RL profile?
> >>
> >> I agree with what Boris says. There are several features that we
> >> excluded from RL on the grounds that they would hamper practical
> >> implementation. I believe that this was one of them. The argument
> >> goes that adding owl:Thing to the profile would require a rule that
> >> adds the relevant type triple for every individual. Of course there
> >> is nothing to prevent RL implementations from dealing correctly with
> >> owl:Thing, but they are not required to do so in order to be
> >> conformant.
> >>
> >> Ian
> >>
> >> On 13 Aug 2009, at 07:41, Boris Motik wrote:
> >>> Hello,
> >>>
> >>> I seem to remember that we explicitly excluded owl:Thing from OWL 2
> >>> RL, on the
> >>> account that it is difficult to support in OWL 2 RL/RDF. The
> >>> objection there was
> >>> that the extension of owl:Thing would become very large. As a
> >>> consequence, the
> >>> rules axiomatizing owl:Thing were removed from OWL 2 RL/RDF; but
> >>> then, to make
> >>> Theorem PR1 hold, we removed owl:Thing from OWL 2 RL as well.
> >>>
> >>> I'm not 100% sure of this, but it seems to me that this is what
> >>> happened.
> >>>
> >>> Regards,
> >>>
> >>> Boris
> >
> > --
> > Dipl.-Inform. Michael Schneider
> > Research Scientist, Dept. Information Process Engineering (IPE)
> > Tel  : +49-721-9654-726
> > Fax  : +49-721-9654-727
> > Email: michael.schneider@fzi.de
> > WWW  : http://www.fzi.de/michael.schneider
> > ======================================================================
> > =
> > FZI Forschungszentrum Informatik an der Universität Karlsruhe
> > Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
> > Tel.: +49-721-9654-0, Fax: +49-721-9654-959
> > Stiftung des bürgerlichen Rechts, Az 14-0563.1, RP Karlsruhe
> > Vorstand: Prof. Dr.-Ing. Rüdiger Dillmann, Dipl. Wi.-Ing. Michael
> > Flor,
> > Prof. Dr. Dr. h.c. Wolffried Stucky, Prof. Dr. Rudi Studer
> > Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
> > ======================================================================
> > =


-- 
Markus Krötzsch
Institute AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe
phone +49 (0)721 608 7362           fax +49 (0)721 608 5998
mak@aifb.uni-karlsruhe.de           www  http://korrekt.org
http://semantic-web-book.org  http://semantic-mediawiki.org

Received on Thursday, 13 August 2009 12:19:20 GMT

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