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Re: A solution to integrate CWA into OWA.

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Fri, 19 Aug 2011 12:26:14 +0100
Cc: <public-owl-dev@w3.org>
Message-Id: <2348B81A-A5C2-43A3-BA7F-C596BDB278F4@cs.man.ac.uk>
To: duanyucong <duanyucong@hotmail.com>
I'm going to be blunt: AFAICT, most of what you've written is gibberish. I say this not to insult, though that's hardly avoidable, but to make clear how off base what you've written is. It may have its roots in some idiosyncratic terminological choices you make...I don't know.

On 18 Aug 2011, at 22:27, duanyucong wrote:

> Dear all,
> I think that there is usually a misunderstanding on the meaning of CWA vs. OWA:

These are really well understood notions with reasonably precise technical meanings. I know people often *are* confused, but I don't think there's a systematic confusion in the literature.

This is a warning sign.

> It is  because of that a discussion might be extended based on implicit understanding of the semantic possibilities of these two concepts.
> for the cases like "...Therefore facts not stored in the database and not derivable from the existing data 
> are considered false in the CWA and unknown or possible in the OWA.... " 
> ---http://www.dsc.ufcg.edu.br/~ulrich/Artigos/MITO SBBD97.pdf 

This is a perfectly reasonable, if not ideal, account.

> My argumentation: 
> 1. in OWA, negation is not "considerated" at all.

Regardless of the scare quotes, this is trivially refutable.

	C => ~D.
	~D => E.
	C => E.
Negation is fully considered.

	C & ~C => owl:Nothing.

Negation is fully (and actively) considered. I.e., unlike the first one, you cannot treat the negation as part of the atomic concept and preserve reasoning.

	a: C&~C.
is inconsistent.

Negation is fully considered.

This is obviously standard first order negation.

> Or in another word, negation is not cognitively available in the mind, and subsequently not available in semantic expressions produced/organized in the mind. 

This is really quite meaningless even on congitive science terms, but is obviously unrelated to the technical, mathematical aspects of OWA/CWA.

Received on Friday, 19 August 2011 11:26:51 UTC

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