Lemma hzmultleh0lth0 { m n : hz } ( ism : hzleh m 0 ) ( isn : hzlth n 0 ) : hzgeh ( m * n ) 0 .
Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.Algebra.Monoids. Require Import UniMath.Algebra.Groups.