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Re: owl:equivalentClass and rds:subClassOf

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 12 Jan 2004 07:51:56 -0500 (EST)
Message-Id: <20040112.075156.133997329.pfps@research.bell-labs.com>
To: bernard.vatant@mondeca.com
Cc: www-rdf-logic@w3.org, holger@SMI.Stanford.EDU

From: "Bernard Vatant" <bernard.vatant@mondeca.com>
Subject: owl:equivalentClass and rds:subClassOf
Date: Mon, 12 Jan 2004 11:53:15 +0100

> Follow-up of a debate in Protégé list.
> 
> Holger Knublauch wrote:
> 
> "... in Protege there is no way to distinguish between
> 
>  :A rdfs:subClassOf :B
>  :B rdfs:subClassOf :A
> 
> and
> 
>  :A owl:equivalentClass :B
> 
> because they are internally mapped into mutual superclasses..."
> 
> The reciprocal rdfs:subClassOf declares a logical equivalence of definition
> (intensional), whereas owl:equivalentClass declares an equivalence at
> instance level (extensional).

Umm,  where did you get this impression?  

> Should those declarations be kept distinct or not by a conformant OWL tool?
> And if yes, what would be the logical relationship, if any, between the
> former and the latter?

As far as the logic underlying OWL is concerned they are exactly the same.

  :A rdfs:subClassOf :B
  :B rdfs:subClassOf :A
entails
  :A owl:equivalentClass :B

and 

  :A owl:equivalentClass :B
entails
  :A rdfs:subClassOf :B
  :B rdfs:subClassOf :A

> Bernard Vatant
> Senior Consultant
> Knowledge Engineering
> Mondeca - www.mondeca.com
> bernard.vatant@mondeca.com

Peter F. Patel-Schneider
Bell Labs Research
Received on Monday, 12 January 2004 07:52:19 GMT

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