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Re: RDF Schema - question on implied typing with rdfs:Class

From: Ivan Herman <ivan@w3.org>
Date: Wed, 06 Apr 2005 10:16:38 +0200
Message-ID: <42539AE6.5050907@w3.org>
To: Hans Teijgeler <hans.teijgeler@quicknet.nl>
Cc: 'Jeremy Wong' <50263336@student.cityu.edu.hk>, semantic-web@w3.org


Hans Teijgeler wrote:
> Jeremy,
>  
> Thanks for the quick response! I still have to get used to your RDF lingo,
> so in order to make sure I'll say it in my own lingo: The typing with
> rdfs:Class of the subclass ex:PassengerVehicle is not required in case the
> recording of the fact that it is a subclass of ex:MotorVehicle is
> guaranteed. If OK:closed, and thanks again.
>  

That is true.

To be very practical: not all RDF environments implement the RDFS entailing rules. If you 
*know* that the RDF data will be processed by a RDFS aware environment then, by virtue of 
the entailing rules, the (ex:PassengerVehicle,rdf:type,rdfs:Class) triplet will be 'added' 
to the triple store (whether 'added' means physically or virtually is besides the point). 
If you want to be on the safe side, you can add the explicit statement, as Jeremy said.

Ivan

> Regards,
> Hans
> 
>   _____  
> 
> From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] On
> Behalf Of Jeremy Wong
> Sent: woensdag 6 april 2005 8:32
> To: Hans Teijgeler; semantic-web@w3.org
> Subject: Re: RDF Schema - question on implied typing with rdfs:Class
> 
> 
> ex:PassengerVehicle rdf:type rdfs:Class is an explicit assertion of what
> you're describing. Your rdfs:subClassOf triple entails ex:PassengerVehicle
> rdf:type rdfs:Class. However, if the assertion ex:PassengerVehicle
> rdfs:subClassOf ex:MotorVehicle is removed and you do not assert
> ex:PassengerVehicle be an instance of rdfs:Class, then ex:PassengerVehicle
> is no more an instance of rdfs:Class unless you retain the explicit
> assertion.
>  
>  
> Jeremy
> 
> ----- Original Message ----- 
> From: Hans Teijgeler <mailto:hans.teijgeler@quicknet.nl>  
> To: semantic-web@w3.org 
> Sent: Wednesday, April 06, 2005 2:09 PM
> Subject: RDF Schema - question on implied typing with rdfs:Class
> 
> Hi,
>  
> I am new in the RDF scene, and I have read most of the related W3C
> Recommendations and the Primer.
>  
> I have a simple question about RDF Schema, with probably a simple answer:
> In the Primer I read that ALL classes need to be typed with rfds:Class. So
> for example:
>     ex:MotorVehicle          rdf:type                rdfs:Class .
>     ex:PassengerVehicle   rdf:type                rdfs:Class .
>     ex:PassengerVehicle   rdfs:subClassOf   ex:MotorVehicle .
>  
> Is there a reason why the subclass ex:PassengerVehicle doesn't inherit being
> an rdfs:Class from the superclass ex:MotorVehicle?
>  
> Regards,
> Hans
>  
> ____________________________
> Hans Teijgeler
> co-author of ISO 15926-2 <http://www.infowebml.ws/ECM4.5/ECM4.5.html> 
> author of ISO 15926-7
> website www.InfowebML.ws <http://www.infowebml.ws/> 
> e-mail hans.teijgeler@quicknet.nl
> phone +31-72-509 2005                     
>  
> 
> 

-- 

Ivan Herman
W3C Communications Team, Head of Offices
C/o W3C Benelux Office at CWI, Kruislaan 413
1098SJ Amsterdam, The Netherlands
tel: +31-20-5924163; mobile: +31-641044153;
URL: http://www.w3.org/People/Ivan/

Received on Wednesday, 6 April 2005 08:16:23 UTC

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