proposition: Lemma hzeqpii {i : hz} : i - 1 != i.
proof: Proof. apply (negf (λ e, hzpluslcan _ _ _ (e @ ! hzplusr0 i))); clear i. confirm_not_equal isdecrelhzeq. Qed.
imports: UniMath.Foundations.NaturalNumbers UniMath.MoreFoundations.PartA UniMath.MoreFoundations.NegativePropositions UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.Algebra.RigsAndRings UniMath.NumberSystems.NaturalNumbersAlgebra