End Diff.
Section Diff_comp.
Context {K : AbsRing} {U V W : NormedModule K}.

Lemma ex_filterdiff_comp'
(f : U -> V) (g : V -> W) x :
ex_filterdiff f (locally x) -> ex_filterdiff g (locally (f x))
-> ex_filterdiff (fun y => g (f y)) (locally x).