fact: Definition filterdiff (f : U -> V) F (l : U -> V) := is_linear l /\ forall x, is_filter_lim F x -> is_domin F (fun y : U => minus y x) (fun y => minus (minus (f y) (f x)) (l (minus y x))).
imports: Coq(Reals Psatz ssreflect) Rcomplements Rbar Lim_seq Iter Hierarchy Continuity Equiv