Definition PS_opp (a : nat -> V) (n : nat) : V := opp (a n).

(* Specifications: *)
Lemma is_pseries_opp (a : nat -> V) (x :K) (l : V) : is_pseries a x l -> is_pseries (PS_opp a) x (opp l).
Lemma ex_pseries_opp (a : nat -> V) (x : K) : ex_pseries a x -> ex_pseries (PS_opp a) x.
Lemma PSeries_opp (a : nat -> R) (x : R) : PSeries (PS_opp a) x = - PSeries a x.
Lemma CV_radius_opp (a : nat -> R) : (CV_radius (PS_opp a)) = (CV_radius a).