W3C home > Mailing lists > Public > public-owl-dev@w3.org > October to December 2007

RE: Some basic questions about OWL-Full

From: Michael Schneider <schneid@fzi.de>
Date: Tue, 23 Oct 2007 23:42:55 +0200
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A04A8819@judith.fzi.de>
To: "Pat Hayes" <phayes@ihmc.us>
Cc: <public-owl-dev@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, <jjc@hpl.hp.com>

Pat Hayes wrote:

>>From: Pat Hayes <phayes@ihmc.us>
>>Subject: Re: Some basic questions about OWL-Full
>>Date: Tue, 23 Oct 2007 08:58:28 -0500
>>
>>>
>>>  >Peter F. Patel-Schneider wrote:
>>>  >>
>>>  >>For homework:  Is EquivalentProperties(owl:sameAs 
>owl:differentFrom)
>>>  >> 	 	       itself inconsisten?
>>>  >>
>>>  >
>>>  >I'm afraid I'm several years' late on my (easier) homework of:
>>>  >    Is (*empty*) itself inconsistent?
>>>
>>>  Yes, in RDF (and conventional FOL). This is the
>>>  only assumption of Tarskian semantic theory, that
>>>  there is something in the universe. One can build
>>>  a 'free' logic which allows an empty universe,
>>>  but then its proof theory can't have the usual
>>>  rules of instantiation and generalization, which
>>>  allow the inferences
>>>
>>>  (forall (x) (foo x))  |==   (foo A) for some
>>>  'new' name A |==  (exists (x)(foo x))
>>>
>>>  Pat
>>
>>I think Jeremy meant an empty KB, i.e., whether OWL Full is trivial or
>>not.
>
>Ah, I see. Sorry. Yes, that question amounts to 
>whether the OWL semantic conditions are 
>internally consistent when transcribed into 
>common logic (or FOL using the holds/app style). 
>Good question!

Hm, seems to me that I did not understand neither Jeremy, nor Peter, nor
you. :) What is meant by "whether OWL Full is trivial or not"? Is this the
question about whether empty OWL-Full ontologies are inconsistent or not?
I.e. whether an empty OWL-Full ontology entails contradictory statements? 

But if I have some arbitrary non-empty ontology O := {A1,...,An}, then O
contains the empty ontology as a sub-ontology. So I would assume that every
statement which is entailed by the empty OWL-Full ontology will also be
entailed by O itself. And if the empty OWL-Full ontology would entail
contradictory statements, then /every/ OWL-Full ontology would entail
contradictory statements, and then OWL-Full semantics would be totaly
broken! Is it this what you (Pat) mean by "whether the OWL semantic
conditions are internally consistent..."? 

Cheers,
Michael

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: Michael.Schneider@fzi.de
Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555

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 Regierungspräsidium Karlsruhe
Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi Studer
Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
Received on Tuesday, 23 October 2007 21:43:16 GMT

This archive was generated by hypermail 2.3.1 : Wednesday, 27 March 2013 09:32:55 GMT