In case the reader is sceptical about the viability of this program, the start of its output follows.let rec merge = lambda a. lambda b. {assume a and b infinite and disjoint} let a1=hd a, b1=hd b in if a1 < b1 then a1::(merge (tl a) b) else {a1 > b1} b1::(merge a (tl b)), mult = lambda a. lambda b. (a * hd b)::(mult a tl b), remove = lambda a. lambda b. { a-b, treat lists as sets. PRE: a & b ascending } if hd a < hd b then (hd a)::(remove tl a b) else if hd a > hd b then remove a tl b else remove tl a tl b, from = lambda n. n::(from (n+1)), { n::(n+1)::(n+2):: ... } products = lambda l. { PRE: l ascending } let rec p = (hd l * hd l) :: { & elts coprime } (merge (mult hd l (merge tl l p)) (products tl l)) in p in let rec composites = products primes, primes = 2 :: (remove (from 3) composites) { ! } in primes {\fB Composites and Primes. \fP}

(2:: (3:: (5:: (7:: ...etc...Output from Composites/Primes Program.

Also see `circular lists' in [Allison (1993)].

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