proposition: Lemma differentiable_comp (U V' W' : normedModType R) (f : U -> V') (g : V' -> W') x : differentiable f x -> differentiable g (f x) -> differentiable (g \o f) x.
proof: Proof. move=> df dg; apply/diff_locallyP; rewrite diff_comp //; by have [? /funext]:= dcomp 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