Section Properties3.
Context {K : AbsRing} {V : NormedModule K}.
exact is_series_scal.
Qed.
exact ex_series_scal.
Qed.
End Properties3.

Lemma is_series_scal_r (c : R) (a : nat -> R) (l : R) :
is_series  a l -> is_series  (fun n => (a n) * c) (l * c).