proposition: Theorem round_ext : forall rnd1 rnd2, ( forall x, rnd1 x = rnd2 x ) -> forall x, round rnd1 x = round rnd2 x.
proof: Proof. intros rnd1 rnd2 Hext x. unfold round. now rewrite Hext. Qed.
imports: Coq(ZArith Reals Lia) Zaux Raux Defs Round_pred Float_prop