Lemma nattohz_inj {m n} : nattohz m = nattohz n -> m = n. Proof. revert m n; exact (invmaponpathsincl _ isinclnattohz). Defined.
Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.Algebra.Monoids. Require Import UniMath.Algebra.Groups.