Exercise 4.2a(1), p. 92

Objective: Prove that (mod-expt b e m) does at least e multiplications, for e ≥ 0.

Base Case: e = 0. Then 0 mults are done, which is at least e.

Induction Hypothesis (I.H.): Assume that (mod-expt b k m) does at least k multiplications, for k < e.