proposition: Lemma differentiableZ (f : V -> W) k x : differentiable f x -> differentiable (k *: f) x.
proof: Proof. by move=> df; apply/diff_locallyP; rewrite diffZ //; have := dscale k 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