proposition: Lemma deriveZ f (k : R) (x v : V) : derivable f x v -> 'D_v (k \*: f) x = k *: 'D_v f x.
proof: Proof. by move=> df; apply: cvg_lim (der_scal 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