W3C home > Mailing lists > Public > www-webont-wg@w3.org > July 2003

Re: Layering bug?

From: Jos De_Roo <jos.deroo@agfa.com>
Date: Thu, 3 Jul 2003 22:33:15 +0200
To: "pat hayes <phayes" <phayes@ihmc.us>
Cc: Jeremy Carroll <jjc@hplb.hpl.hp.com>, www-webont-wg@w3.org, www-webont-wg-request@w3.org
Message-ID: <OF6EDC00E8.57F5039C-ONC1256D58.006FC1F9-C1256D58.0070EC81@agfa.be>

It is painful, but I will try again to live with
owl:Class owl:equivalentClass rdfs:Class.
owl:Thing owl:equivalentClass rdfs:Resource.
and consider
owl:Thing owl:oneOf _:x.
as an inconsistent OWL Full document.
I guess there are also inconsistent statements
about owl:Class ??

Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/

                      pat hayes                                                                                                        
                      <phayes@ihmc.us>         To:       Jeremy Carroll <jjc@hplb.hpl.hp.com>                                          
                      Sent by:                 cc:       www-webont-wg@w3.org                                                          
                      www-webont-wg-req        Subject:  Re: Layering bug?                                                             
                      2003-07-03 07:55                                                                                                 

>Jeremy Carroll wrote:
>>How about this:
>>eg:c rdf:type owl:Class .
>>eg:d rdf:type owl:Class .
>>eg:ap rdf:type AnnotationProperty .
>>owl:Thing owl:oneOf rdf:nil .
>>eg:c eg:ap eg:d .
>>I think this holds in OWL Full but not in OWL DL, yet it is within
>>the syntactic subset.
>As Mehrdad points out this is actually an OWL DL entailment,
>since owl:Thing is non-empty.
>Updated problem case is:
>eg:p rdf:type owl:ObjectProperty .
>eg:q rdf:type owl:ObjectProperty .
>owl:Thing owl:oneOf _:b .
>   _:b rdf:first eg:i .
>   _:b rdf:rest rdf:nil.
>   eg:i rdf:type owl:Thing.
>eg:i eg:p eg:i .
>  entails
>eg:i eg:q eg:i .
>True in OWL full, since the universe has only one element thus eg:q
>and eg:p are the same property.

Well, but the universe also contains all the RDFS properties and
classes and rdf:nil and all literal values, for example. So things
are a lot weirder than this example might suggest, since it would
also follow that for example:

rdf:type owl:sameAs owl:Thing .

(choose your favorite zany identity) and God alone knows what the
consequences of all these would be.  Certainly this would be
inconsistent in any datatyped interpretation, eg consider

xsd:string owl:sameAs xsd:integer .


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Received on Thursday, 3 July 2003 16:34:35 UTC

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