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Re: Layering bug?

From: pat hayes <phayes@ihmc.us>
Date: Thu, 3 Jul 2003 12:55:43 -0500
Message-Id: <p0600123abb2a0ec56520@[10.0.100.7]>
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: www-webont-wg@w3.org

>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 .
>>
>>entails
>>
>>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 .

Pat

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Received on Thursday, 3 July 2003 13:55:50 GMT

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