(** * Convergence circle *)
(** A power series is always defined at 0 *)
Section ConvergenceCircle.
Context {K : AbsRing} {V : NormedModule K}.

(* Specifications: *)
Lemma is_pseries_0 (a : nat -> V) :
is_pseries a zero (a O).
Lemma ex_pseries_0 (a : nat -> V) :
ex_pseries a zero.