proposition: Lemma Exercise6_33a1: a ^c (b *c b) = a ^c b.
proof: Proof. case: (finite_or_infinite (proj32 hb)) => fb; last by rewrite csquare_inf. case: iab => fa; last by rewrite csquare_inf. move: fb => /NatP fb. by rewrite cpow_pow {1} (cpow_inf fa fb (nesym (proj2(clt_leT clt_01 hb)))). Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype)