fact: Parameter add_UP_correct : forall p x y, valid_ub x = true -> valid_ub y = true -> (valid_ub (add_UP p x y) = true /\ le_upper (Xadd (toX x) (toX y)) (toX (add_UP p x y))).
imports: Coq(ZArith Reals) Flocq(Zaux Raux) Xreal Basic