proposition: Lemma differentiableZl (k : V -> R) (f : W) x : differentiable k x -> differentiable (fun z => k z *: f) x.
proof: Proof. by move=> df; apply/diff_locallyP; rewrite diffZl //; have [] := dscalel f df. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum matrix interval) mathcomp(mathcomp_extra boolp classical_sets functions) reals signed topology prodnormedzmodule normedtype landau forms