proposition: Lemma abszX (n : nat) m : `|m ^+ n| = `|m| ^ n.
proof: Proof. by elim: n => // n ihn; rewrite exprS expnS abszM ihn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)