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Re: Layering bug?

From: pat hayes <phayes@ihmc.us>
Date: Thu, 3 Jul 2003 17:49:40 -0500
Message-Id: <p0600123ebb2a58eace5c@[10.0.100.7]>
To: "Jos De_Roo" <jos.deroo@agfa.com>
Cc: www-webont-wg@w3.org

>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 ??

Sure, such as

owl:Class rdf:type owl:Class .

which (under the identities assumed in Full) is both RDFS-valid and 
an OWL-inconsistency.  Welcome the wonderful world of layering :-)

Pat

>
>--
>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?                                                            
> 
>uest@w3.org                                                                                                     
> 
>                                                                                                                                     
> 
>                                                                                                                                     
>                       2003-07-03 
>07:55                                                                                                
> 
>PM                                                                                                              
> 
>                                                                                                                                     
> 
>                                                                                                                                     
>
>
>
>
>
>>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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IHMC	(850)434 8903 or (650)494 3973   home
40 South Alcaniz St.	(850)202 4416   office
Pensacola			(850)202 4440   fax
FL 32501			(850)291 0667    cell
phayes@ihmc.us       http://www.ihmc.us/users/phayes
Received on Thursday, 3 July 2003 18:49:43 GMT

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