End AdmissibleClosure.
Arguments chain_closed [T].
Prenex Implicits chain_closed.

(* Specifications: *)
(* diagonal of an admissible set of pairs is admissible *)
Lemma chain_clos_diag (T : cpo) (s : Pred (T * T)) :
chain_closed s -> chain_closed [Pred t : T | (t, t) \In s].