(** Addition *)

Lemma Lim_plus (f g : R -> R) (x : Rbar) :
ex_lim f x -> ex_lim g x ->
ex_Rbar_plus (Lim f x) (Lim g x) ->
Lim (fun y => f y + g y) x = Rbar_plus (Lim f x) (Lim g x).