Section Facts.
Variable A : Type.
(** *** Generic facts *)
(** Destruction *)
(** *** Head and tail *)
(************************)
(** *** Facts about [In] *)
(************************)
(** Characterization of [In] *)

(* begin hide *)
(* Deprecated *)
Theorem app_assoc_reverse : forall l m n:list A, (l ++ m) ++ n = l ++ m ++ n.