Variable X : Type.
Section fixL.
Variables (LX : enumT X).
Fixpoint T_list (n : nat) : list (list X) :=
match n
with
| 0 => [ [] ]
| S n => T_list n ++ [ x :: L | (x,L) ∈ (L_T X n × T_list n) ]
end.

(* Specifications: *)
Lemma T_list_cum : cumulative T_list.
End fixL.
Lemma T_list_el LX l :
exists n, l el T_list LX n.