proposition: Lemma expfV (x : R) (i : int) : (x ^ i) ^-1 = (x ^-1) ^ i.
proof: Proof. by rewrite invr_expz exprz_inv. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)