fact: Definition diff (F : filter_on V) (_ : phantom (set (set V)) F) (f : V -> W) := (get (fun (df : {linear V -> W}) => continuous df /\ forall x, f x = f (lim F) + df (x - lim F) +o_(x \near F) (x - lim F))).
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum matrix interval) mathcomp(mathcomp_extra boolp classical_sets functions) reals signed topology prodnormedzmodule normedtype landau forms