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RE: Comments on * DRAFT * Rules Working Group Charter $Revision: 1.60 $

From: Gerd Wagner <wagnerg@tu-cottbus.de>
Date: Wed, 24 Aug 2005 11:56:31 +0200
To: "'Jim Hendler'" <hendler@cs.umd.edu>, "'Dieter Fensel'" <dieter.fensel@deri.org>, <public-rule-workshop-discuss@w3.org>
Message-Id: <20050824095753.0D1C8508206@smtp2.TU-Cottbus.De>

>> The only rule language that FOL is a superset of (modulo a 
>> mapping) is SWRL - an untested newcomer. And of Horn Datalog, 
>> which is near-useless. All the
>> real rule-based languages don't map into FOL AFAIK.
> 
> Am I the only one confused?  Why is "Horn logic with a minimal model" 
> so preferable to "Horn Datalog"?

For two simple reasons:

1) because Datalog does not have any form of negation, which is 
needed, however, in any practically useful language

2) minimal/stable model semantics is preferable since it is
used in all major practical (non-academic) logic languages
such as SQL, OCL, Prolog, JESS, ILOG JRules, etc.

Classical FOL is an academic language, which is good for
explaining/doing mathematics (where knowledge is monotonic),
but not for specifying/processing ordinary information,
which is inherently nonmonotonic.

-Gerd

--------------------------------------------
Professor Gerd Wagner 
http://www.informatik.tu-cottbus.de/~gwagner
Email: G.Wagner@tu-cottbus.de
Tel: (+49 355) 69 2397
Institute of Informatics
Brandenburg University of Technology 
at Cottbus, Germany
Received on Wednesday, 24 August 2005 09:58:08 GMT

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