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Re: question about rules where the conclusions are rules

From: <jos.deroo@agfa.com>
Date: Sun, 23 Oct 2005 23:16:16 +0200
To: pfps@comcast.net
Cc: pfps@research.bell-labs.com, public-rule-workshop-discuss@w3.org
Message-ID: <OF4B720849.274179BB-ONC12570A3.007287F8-C12570A3.0074D61B@agfa.com>

>>>>how does one call rules written in the form of A => (B => (C => D))
>>>>which is of course the same as (A & B & C) => D
>>>>but I was just wondering wether there was a special name for the
>>>>former form..
>>>I don't understand your question.
>>>Why wouldn't you call them ill-formed?  Many, probably most, rule 
>>>formalisms don't allow such rules.
>>My question is wether there is a name for rules such as e.g.
>>@forAll :U, :V, :X, :Y, :Z.
>>{:U :hasProblem :V}
>>{{:X r:applyToProblem :V.
>>  :X r:hasInvestigation :Y}
>> =>
>> {{:Y r:modalityType :Z}
>>  =>
>>  {:U :isRecommended :Z}}}. 
>>I actually have no trouble to run such rules
>>and am investigating their utility in the context
>>of subgoal reordering. I just wanted to make sure
>>that I don't invent my own name for things that
>>are eventually having a well known name.
>I still don't understand.  How are you running these rules?  What do 
>they mean? 
>You can define these "nested" rules as an alternative syntax for some 
>other sort of rule.  However, if you really want the rules to act like 
>they look, then it seems to me that you will be inferring *new* rules. 
>How, then, does this interact with your rule system?
>Again, without you providing a meaning for these rules, I don't see a 
>way to help.

For those "nested" rules I want to keep the first order logic
semantics, but am experimenting with an operational semantics
to indeed infer *new* rules and it is cwm that is hapily running
such rules. For a backward chainer like euler it is different,
but I'm having an experimental premature version that runs.

The basic observation about "nested" rules is that there is
no need to reorder single triple premises. The target is be
explicit about the ordering (using "nested" rules) and have
a means to write rules that derive rules, so that machines
can be used to derive (optimal) explicitly reordered rules.

Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Sunday, 23 October 2005 21:16:33 UTC

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