Lemma plusNonnegativeRationals_minus_l : ∏ q r : NonnegativeRationals, (q + r) - q = r. Proof. intros q r. rewrite iscomm_plusNonnegativeRationals. now apply plusNonnegativeRationals_minus_r. Qed.
Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.MoreFoundations.Sets. Require Import UniMath.MoreFoundations.Orders. Require Import UniMath.RealNumbers.Sets. Require Import UniMath.RealNumbers.Fields. Require Import UniMath.OrderTheory.Lattice.Lattice. Require Import UniMath.RealNumbers.Prelim.