defn zero = \s. \z. z defn succ = \n. \s. \z. s (n s z) norm one = succ zero norm two = succ one norm three = succ two defn plus = \n. \k. n succ k norm four = plus one three defn times = \n. \k. n (plus k) zero norm twelve = times four three defn exp = \n. \k. k (times n) one norm n4096 = exp two twelve defn pair = \x. \y. \k. k x y defn pred2 = \n. n (\p. p (\x. \y. pair (succ x) x)) (pair zero zero) norm p0_0 = pred2 zero norm p1_0 = pred2 one norm p2_1 = pred2 two defn pred = \n. pred2 n (\x. \y. y) norm n4095 = pred n4096