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Re: Universal Quantification

From: Thomas B. Passin <tpassin@comcast.net>
Date: Wed, 05 May 2004 21:35:44 -0400
Message-ID: <40999670.3020206@comcast.net>
To: www-rdf-logic@w3.org

Stephen Rhoads wrote:

> 
>>
>> :Quote2
>>     a owl:Class ;
>>     rdfs:subClassOf
>>     [ a owl:Restriction ;
>>       owl:onProperty :effectivePeriod ;
>>       owl:allValuesFrom :Duration
>>     ] ;
>>     rdfs:subClassOf
>>     [ a owl:Restriction ;
>>       owl:onProperty :effectivePeriod ;
>>       owl:someValuesFrom :Duration
>>     ] .
> 
> 
> Would you actually use an allValuesFrom and someValuesFrom for the same 
> property in the same class axiom?  That seems contradictory to me.  
> someValuesFrom doesn't preclude there being other values; allValuesFrom 
> does.
> 

someValuesFrom requires there to be at least one value from the 
specified class, and allValuesFrom requires that if there are any 
values, they all come from the specified class (but there could be no 
values at all).  So there has to be at least one, and that one and any 
more all have to come from the specified class.

Not exactly intuitive, eh?

Cheers,

Tom P
Received on Wednesday, 5 May 2004 21:36:00 UTC

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