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Carl --

I think that the (* intersect) will turn out to be generally useful.
It provides an explicit way to represent what is going on, and so just
for documentation purposes it is very useful.  And, as you process
an intersection, there may be several ways to "get stuck", e.g.
	(* intersect (* prefix "2000-01")
		     (* range date "1999" "2005"))
might an intermediate term you end up with, and you reduction engine
might not know how to deal with it.  So, with (* intersect) available
as a primitive, you can just leave this piece in this form, and process
the other parts.
Also, I like the logical completeness of having both (* set) and (* intersect).

	Cheers,
	Ron
------------------------------------------------------------------------------
From: Carl Ellison <cme@cybercash.com>
Subject: Re: *-forms
Cc: spki@c2.net, blampson@microsoft.com

At 06:43 AM 4/5/97 EST, Ron Rivest wrote:
>	-- we introduce a new *-form:
>
>		(* intersect s1 s2 ... sk)

This is reasonably clean but I'm not sure there's an advantage to it over 
deciding in the 5-tuple engine not to do cross products (as per my previous 
message).


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