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_radius_plus (a b : nat -> R) :
Rbar_le (Rbar_min (CV_radius a) (CV_radius b)) (CV_radius (PS_plus a b)).