Re: On production rules and phase I&II

Peter F. Patel-Schneider wrote:
> I don't understand which universe I've fallen into here.
>
> In my universe, production rule systems derived from OPS5.  
>
> In my universe, OPS5 allowed rules like
> 	(p (parent ^parent <x> ^child <y>)
> 	   (ancestor ^ancestor <y> ^descendant <z>)
> 	   -->
> 	   (make ancestor ^ancestor <x> ^descendant <z>))
>
> In my universe, this was a recursive rule.
>
> What is different in this universe?
>   
My understanding is that Hassan - riogthly - pointed out that using a
production rule like the above (and its evaluator), one can implements a
recurrsive deduction rule stating that parents of ancestors are
themselves ancestors.

Thus, the situation is like implementing the evaluation of a recursive
deduction rule using a while-block in an imperative programme: this
programme is not recursive even though it uimplements something which is
recursive.

Hassan, did I got your point?

Francois

Received on Wednesday, 8 March 2006 13:56:36 UTC