proposition: Theorem _paco13_fold: forall r, gf (upaco13 gf r) <13== paco13 gf r.
proof: Proof. intros. apply uncurry_adjoint1_13. eapply le1_trans; [| apply _paco_fold]. apply le1_refl. Qed.
imports: Program.Basics Paco(paconotation_internal paco_internal pacotac_internal)