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Re: Denotation of owl:Class

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Fri, 25 Apr 2003 14:00:17 +0100 (BST)
To: Brian McBride <bwm@hplb.hpl.hp.com>
cc: RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.44.0304251349290.13980-100000@mail.ilrt.bris.ac.uk>

On Fri, 25 Apr 2003, Brian McBride wrote:

> What is bothering me is that the denotation of owl:Class seems to depend on
> what is processing it, and I guess I'm making the naive user assumption,
> that owl:Class denotes the same thing (horribly deep philosophical rathole
> opens in front of me) wherever its used i.e. either
>
>    rdfs:Class rdfs:subClassOf owl:Class .
>
> is true in the 'real world' or its not.  If its true, then why is owl:Class
> needed?  If its false, why is OWL FULL asserting its true.

It's not a true/false distinction, it's a theorem/nontheorem one, I
think. owl:Class exists so that OWL DL and OWL Lite reasoners don't have
to tackle the knots at the top of RDF's class hierarchy.

jan (IANADL)

PS. Incidentally,

	a rdfs:subClassOf b .
	b rdfs:subClassOf a .

don't mean that a and b denote the same thing; it means their class
extensions are the same.

-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/
Work #90: As many pseudo-intellectual sycophants as necessary to make one
inarticulate scotsman think he's a genius in command of The Profound.
Received on Friday, 25 April 2003 09:00:38 EDT

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