proposition: Lemma hzsign_natnattohz m n : - natnattohz m n = natnattohz n m.
proof: Proof. reflexivity. Defined.
imports: UniMath.Foundations.NaturalNumbers UniMath.MoreFoundations.PartA UniMath.MoreFoundations.NegativePropositions UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.Algebra.RigsAndRings UniMath.NumberSystems.NaturalNumbersAlgebra