(** ** Cardinal is a morphism *)

(* Specifications: *)
Lemma Equal_cardinal : forall s s', s[=]s' -> cardinal s = cardinal s'.
Add Morphism cardinal with signature (Equal ==> Logic.eq) as cardinal_m.
Lemma Equal_cardinal : forall s s', s[=]s' -> cardinal s = cardinal s'.
#[global]
Instance cardinal_m : Proper (Equal==>Logic.eq) cardinal.