proposition: Lemma differentiableD (f g : V -> W) x : differentiable f x -> differentiable g x -> differentiable (f + g) x.
proof: Proof. by move=> df dg; apply/diff_locallyP; rewrite diffD //; have := dadd df dg. 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