Section ComposeApplicative.
Variable (F G :Applicative).
Let FG (a:Type) := F (G a).
Definition Compose_pure (a:Type) (x:a) : FG a :=
pure F (pure G x).
Definition Compose_ap (a b:Type) (f:FG (a -> b)) (x:FG a) : FG b :=
ap (ap (pure F (fun g x => ap g x)) f) x.

Lemma Compose_interchange a b (f : FG (a -> b)) x :
Compose_ap f (Compose_pure x) = Compose_ap (Compose_pure (fun g => g x)) f.