Re: W3C RIF: "recursive rules" vs "recursive terms"

Michael Kifer wrote:

> Many years ago I stumbled upon a CLIPS manual where it was described how to
> avoid computing the entire model. It was essentially a description of a
> rudimentary Magic Set transformation.  The date on that manual was 1983 or
> 1984 - a year or two before the first magic set paper appeared.
> 
> The point is that one can write bad rules bottom up or top down - doesn't
> matter. You can avoid computing the entire model, using smart techniques. That
> CLIPS manual author of > 20 years ago was definitely very smart. Too bad he
> didn't think that his trick was worth a publication :-)
> 
> 	--michael  

"Magic Set" techniques have been [re]discovered in many guises by several
people. In France, for example, it is better known as "La Méthode Alexandre"
due to Jean-Marc Kerisit [J. Rohmer, R. Lescoeur, J-M Kerisit: The Alexander
Method - A Technique for The Processing of Recursive Axioms in Deductive
Databases. New Generation Computing 4(3): 273-285 (1986)]. That was the PhD
thesis of J-M Kerisit at U. of Paris 7 (88) and was worked out independently
of the Bancilhon, Ramakrishnan, etc., Magic Set formulation (ca. 86 as well).

This is true for many ideas, BTW. Another essential idea that has been
[re]invented several times by several people under many apparently
unrelated guises in several disciplines is the notion of continuation and
monad in FP, difference lists an such incomplete data structures in LP,
accumulators in LIFE, Didier Rémy's extensible records in CAML, Montague
grammars in linguistics, Categorial grammars in NLP, etc., ... It was
reinvented again by Harold Boley today - although IMHO as an overkill -
as a trick to accommodate the felxible arity of slotted terms ... :-D

Nothing is new under the sun... The longer my research experience, the
truer this truism seems to be! :-P

Merry Times and Happy Feet To All! :-)

-hak
-- 
Hassan Aït-Kaci
ILOG, Inc. - Product Division R&D
tel/fax: +1 (604) 930-5603 - email: hak @ ilog . com

Received on Wednesday, 20 December 2006 00:21:25 UTC