(* misc expec *)

Add Parametric Morphism (A: Set): (@expec A)
  with signature (@ext_eq A nat) ==> (@ext_eq (ne_tree.T A) R)
  as expec_ext_morph.

Lemma expec_le (X: Set) (f g: X -> nat) (t: ne_tree.T X): (forall x, ne_tree.In x t -> (f x <= g x)%nat) -> expec f t <= expec g t.