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Re: ISSUE-55 (owl:class): owl:class v. rdfs:class

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Mon, 12 Nov 2007 23:11:46 -0500
Message-Id: <B44C8521-F9F5-4F63-A2B8-3B30965669E2@gmail.com>
To: OWL Working Group WG <public-owl-wg@w3.org>

Here is my understanding of why there is a distinction:

http://www.w3.org/TR/rdf-schema/#ch_class says:

"A class may be a member of its own class extension and may be an  
instance of itself."

This is not the case in OWL-DL, where classes are not instances.

http://www.w3.org/TR/owl-ref/ says:

NOTE: owl:Class is defined as a subclass of rdfs:Class. The rationale  
for having a separate OWL class construct lies in the restrictions on  
OWL DL (and thus also on OWL Lite), which imply that not all RDFS  
classes are legal OWL DL classes. In OWL Full these restrictions do  
not exist and therefore owl:Class and rdfs:Class are equivalent in  
OWL Full.


On Nov 12, 2007, at 10:41 PM, OWL Working Group Issue Tracker wrote:

> ISSUE-55 (owl:class): owl:class v. rdfs:class
> http://www.w3.org/2007/OWL/tracker/issues/
> Raised by: James Hendler
> On product:
> At ISWC 07, it has come up in several presentations that a great  
> many OWL Full ontologies (in RDFS esp) become OWL DL if you just  
> change rdfs:class to owl:class - while it is acknowledged that this  
> makes a semantic change, many people said they simply just do it in  
> their tools.
> Given the improved understanding at this point of things like  
> punning, the WG might want to revisit this issue and see if there  
> is a technical solution that could be considered - or at least make  
> a clear and precise statement as to why we are unable to do so and  
> why this dichotomy must consider to exist (as unfortunate as that is)
Received on Tuesday, 13 November 2007 04:11:58 UTC

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