proposition: Lemma mulzn_eq1 m (n : nat) : (m * n == 1) = (m == 1) && (n == 1).
proof: Proof. by case: m => m /=; [rewrite -PoszM [_==_]muln_eq1 | case: n]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)