proposition: Lemma NRNRtoR_opp : ∏ x y : NonnegativeReals, NRNRtoR y x = - NRNRtoR x y.
proof: Proof. intros x y. apply pathsinv0, NR_to_hr_opp. Qed.
imports: UniMath.Algebra.Groups UniMath.Foundations.Preamble UniMath.MoreFoundations.Orders UniMath.MoreFoundations.Tactics UniMath.OrderTheory.Lattice.Lattice UniMath.RealNumbers.Prelim UniMath.RealNumbers.Sets UniMath.RealNumbers.NonnegativeRationals UniMath.RealNumbers.NonnegativeReals