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Re: On production rules and phase I&II

From: Francois Bry <bry@ifi.lmu.de>
Date: Wed, 08 Mar 2006 11:52:49 +0100
Message-ID: <440EB781.3010506@ifi.lmu.de>
To: Hassan At-Kaci <hak@ilog.com>
CC: public-rif-wg@w3.org

Hassan At-Kaci wrote:
> Now PRs are NOT driven by names. Since a rule is not using a relational
> or functional name in its head to drive the rule's call, it is simply
> not possible to have recursive rules.
> Does it mean PR's cannot compute iteratively? Certainly not: there is
> an underlying loop that acytivates the rules based on the data present
> in the working memory (or Extensional DB, or Fact Base, etc...). Viz.,
>     WHILE   [some rules match some objects in the WM]
>     DO      [choose a rule and all the objects it matches]
>                 [do the action of the rules on all these objects.]
> In conclusion, while it is possible to simulate one system in the
> other (e.g., by mere Turing equivalence), it may be contended that
> the translations to and from each side (PRs and Pure Horn) are, IMHO,
> non-trivial and non-intuitive.
> So, Frank is basically right: what Harold et al.'s Road Map defines
> as "pure PRs" is computationally uninteresting and its rendition in
> Pure Horn is likely to be at odds with a rendition for Full PR.

Received on Wednesday, 8 March 2006 10:52:55 UTC

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