Section PACO0.
(** ** Signatures *)
Record sig0T  :=
exist0T {
}.
Definition uncurry0  (R: rel0): rel1 sig0T :=
fun x => R.
Definition curry0  (R: rel1 sig0T): rel0 :=
R (@exist0T).

Lemma uncurry_map0 r0 r1 (LE : r0 <0== r1) : uncurry0 r0 <1== uncurry0 r1.