∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {E : Type u_2} [inst_1 : NormedAddCommGroup E]
  [inst_2 : NormedSpace 𝕜 E] {H : Type u_3} [inst_3 : TopologicalSpace H] {I : ModelWithCorners 𝕜 E H} {M : Type u_4}
  [inst_4 : TopologicalSpace M] [inst_5 : ChartedSpace H M] {E' : Type u_5} [inst_6 : NormedAddCommGroup E']
  [inst_7 : NormedSpace 𝕜 E'] {H' : Type u_6} [inst_8 : TopologicalSpace H'] {I' : ModelWithCorners 𝕜 E' H'}
  {M' : Type u_7} [inst_9 : TopologicalSpace M'] [inst_10 : ChartedSpace H' M'] {E'' : Type u_8}
  [inst_11 : NormedAddCommGroup E''] [inst_12 : NormedSpace 𝕜 E''] {H'' : Type u_9} [inst_13 : TopologicalSpace H'']
  {I'' : ModelWithCorners 𝕜 E'' H''} {M'' : Type u_10} [inst_14 : TopologicalSpace M''] [inst_15 : ChartedSpace H'' M'']
  {f : M → M'} (x : M) {s : Set M} {g : M' → M''} {u : Set M'},
  MDifferentiableWithinAt I' I'' g u (f x) →
    MDifferentiableWithinAt I I' f s x →
      s ⊆ f ⁻¹' u →
        UniqueMDiffWithinAt I s x →
          mfderivWithin I I'' (g ∘ f) s x = (mfderivWithin I' I'' g u (f x)).comp (mfderivWithin I I' f s x)