Notation WO := (WO A B).#[universes(template)]
Inductive WO (A : Type) (B : A -> Type) : Type :=
  sup : forall (a:A) (f:B a -> WO A B), WO A B.Inductive le_WO : WO -> WO -> Prop :=
    le_sup : forall (a:A) (f:B a -> WO) (v:B a), le_WO (f v) (sup _ _ a f).Inductive le_WO : WO -> WO -> Prop :=
    le_sup : forall (a:A) (f:B a -> WO) (v:B a), le_WO (f v) (sup _ _ a f).

(* Specifications: *)
Lemma le_WO_inv x y : le_WO x y -> exists a f v, f v = x /\ sup _ _ a f = y.
Theorem wf_WO : well_founded le_WO.