#[deprecated(use = snd_list_prod)]
Notation map_snd_list_prod := snd_list_prod (only parsing).
(** Sum of elements of a list of [nat]: [list_sum] *)
Definition list_sum l := fold_right plus 0 l.

Lemma length_list_power (A B:Type)(l:list A) (l':list B):
length (list_power l l') = (length l')^(length l).