proposition: Lemma Fminus2_correct : forall x y : float2, Fminus2 x y = (x - y)%R :>R.
proof: Proof. intros x y. unfold Fminus2. generalize (Fshift2_correct x y). destruct (Fshift2 x y) as ((mx, my), e). intros (Hx, Hy). rewrite <- Hx, <- Hy. unfold float2R, F2R. simpl. rewrite minus_IZR. apply Rmult_minus_distr_r. Qed.
imports: Coq(ZArith Reals Lia) Flocq(Raux Defs Float_prop Operations) Gappa_definitions