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Re: Data models as constraints

From: Hassan At-Kaci <hak@ilog.com>
Date: Tue, 16 Jan 2007 16:45:59 +0100
Message-ID: <45ACF337.3070800@ilog.com>
To: Gerd Wagner <wagnerg@tu-cottbus.de>
CC: W3C RIF WG <public-rif-wg@w3.org>

Gerd Wagner wrote:

>>I have finalized the writeup on data models as constraints. 
>>It is available as
>>http://koala.ilog.fr/wiki/pub/Main/HassanAitKaci/semwebclp.pdf
>>Comments are welcome.
> 
> 
> Hassan, it seems that you have completely ignored the 
> fundamental issue of negation-as-failure (NaF), also 
> called "negation-by-default", and the related issue 
> of open vs. closed predicates in your paper. 
> 
> Why? Because you didn't consider that (yet) in your 
> OSF formalism?

Hi Gerd,

Thanks for your comment on my paper: you must be the fastest reader
that I have come across in my life! ;-)

Re. your comment, I must say thay I do not quite understand what it
has to do with either the topic of the article, nor  what it means.
What I wrote about is simple: because CLP makes rules and constraints
orthogonal, it offers a way to use rules over arbitrary data models
- not just data and FOTs. I then focused on the OSF and DL formalisms
seen as constraint systems for objects and inheritance. The nature of
the rules is *not* important and may be of all kinds including Horn,
(with or without negations or all kinds), Production, YouNameIt, ...

> How can you capture SQL, Prolog and production rules
> without supporting NaF?

Again the focus of my paper is *NOT* on the rules but (as the title
states it clearly) about *data models as constraint systems*.

Also, the nature of the paper is that of a (semi-formal) tutorial
- not an exhaustive survey about all known or possible ways to
conjugate rules and data. Perhaps you should write such an article?
:-)

This notwithstanding, the way negation is handled for OSF terms (see
Section 3.1.5) implicitly uses a CWA on the set of sort. I admit that
I should make this fact clear.

Finally, this is just a journal article, not a book! Isn't a 40-page
paper, in 10pt font fullpage layout, long enough for you?  :-)

At any rate, I am sorry that you find my work of debatable interest
for your needs, and I apologize for disappointing your expectations.

Be that a it may, thanks again for caring to give me some feedback
with your comments.

> -Gerd

Regards,

-hak
-- 
Hassan At-Kaci
ILOG, Inc. - Product Division R&D
tel/fax: +1 (604) 930-5603 - email: hak @ ilog . com
Received on Tuesday, 16 January 2007 15:46:58 GMT

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