proposition: Lemma is_derive_ext : forall (f g : K -> V) (x : K) (l : V), (forall t : K, f t = g t) -> is_derive f x l -> is_derive g x l.
proof: Proof. intros f g x l Heq Hf. apply: filterdiff_ext_locally Hf. by apply filter_forall. Qed.
imports: Coq(Reals Psatz ssreflect) Rcomplements Rbar Lim_seq Iter Hierarchy Continuity Equiv