proposition: Lemma Rabs_Ropp : ∏ x : Reals, (Rabs (- x)%R = Rabs x).
proof: Proof. intros x. rewrite <- (NRNRtoR_RtoNRNR x). apply iscomm_maxNonnegativeReals. 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