proposition: Lemma CReal_plus_le_reg_l : forall x y z : CReal, x + y <= x + z -> y <= z.
proof: Proof. intros x y z Hlt contra. apply Hlt. apply CReal_plus_lt_compat_l; exact contra. Qed.
imports: QArith Qpower Qabs Qround Logic.ConstructiveEpsilon Lia Lqa QExtra ConstructiveExtra