{z : A} : (forall i, x i $-> z) -> cat_coprod I x $-> z := cat_prod_corec I (A:=A^op) (x:=x).
Require Import Basics.Overture Basics.Tactics Basics.Decidable. Require Import Types.Bool. Require Import WildCat.Core WildCat.Equiv WildCat.Forall WildCat.NatTrans