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_bij1_0 r : curry0 (uncurry0 r) <0== r.