Section PS_plus.
Context {K : AbsRing} {V : NormedModule K}.
Definition PS_plus (a b : nat -> V) (n : nat) : V := plus (a n)  (b n).
End PS_plus.

Lemma CV_disk_plus (a b : nat -> R) (x : R) :
(CV_disk a x) -> (CV_disk b x)
-> (CV_disk (PS_plus a b) x).