l3lab/ntp-mathlib huggingface dataset:
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`.
This lemma proves this estimate assuming additionally that two of the spaces live in the same
universe, to make an induction possible. Use instead `norm_iteratedFDerivWithin_comp_le` that
removes this assumption. -/
theorem norm_iteratedFDerivWithin_comp_le_aux {Fu Gu : Type u} [NormedAddCommGroup Fu]
    [NormedSpace 𝕜 Fu] [NormedAddCommGroup Gu] [NormedSpace 𝕜 Gu] {g : Fu → Gu} {f : E → Fu} {n : ℕ}
    {s : Set E} {t : Set Fu} {x : E} (hg : ContDiffOn 𝕜 n g t) (hf : ContDiffOn 𝕜 n f s)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We argue by induction on `n`, using that `D^(n+1) (g ∘ f) = D^n (g ' ∘ f ⬝ f')`. The successive
    derivatives of `g' ∘ f` are controlled thanks to the inductive assumption, and those of `f'` are
    controlled by assumption.
    As composition of linear maps is a bilinear map, one may use
    `ContinuousLinearMap.norm_iteratedFDeriv_le_of_bilinear_of_le_one` to get from these a bound
    on `D^n (g ' ∘ f ⬝ f')`. -/
  induction' n using Nat.case_strong_induction_on with n IH generalizing Gu
  · simpa [norm_iteratedFDerivWithin_zero, Nat.factorial_zero, algebraMap.coe_one, one_mul,
      pow_zero, mul_one, comp_apply] using hC 0 le_rfl
  

Proof state:
case hi
𝕜 : Type u_1
inst✝¹² : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝¹¹ : NormedAddCommGroup D✝
inst✝¹⁰ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace 𝕜 E
F : Type uF
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace 𝕜 F
G : Type uG
inst✝⁵ : NormedAddCommGroup G
inst✝⁴ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
Fu : Type u
inst✝³ : NormedAddCommGroup Fu
inst✝² : NormedSpace 𝕜 Fu
f : E → Fu
s : Set E
t : Set Fu
x : E
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
n : ℕ
IH :
  ∀ m ≤ n,
    ∀ {Gu : Type u} [inst : NormedAddCommGroup Gu] [inst_1 : NormedSpace 𝕜 Gu] {g : Fu → Gu},
      ContDiffOn 𝕜 (↑m) g t →
        ContDiffOn 𝕜 (↑m) f s →
          (∀ i ≤ m, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C) →
            (∀ (i : ℕ), 1 ≤ i → i ≤ m → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) →
              ‖iteratedFDerivWithin 𝕜 m (g ∘ f) s x‖ ≤ ↑m ! * C * D ^ m
Gu : Type u
inst✝¹ : NormedAddCommGroup Gu
inst✝ : NormedSpace 𝕜 Gu
g : Fu → Gu
hg : ContDiffOn 𝕜 (↑(Nat.succ n)) g t
hf : ContDiffOn 𝕜 (↑(Nat.succ n)) f s
hC : ∀ i ≤ Nat.succ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ Nat.succ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
⊢ ‖iteratedFDerivWithin 𝕜 (Nat.succ n) (g ∘ f) s x‖ ≤ ↑(Nat.succ n)! * C * D ^ Nat.succ n

Next tactic:
have M : (n : ℕ∞) < n.succ := Nat.cast_lt.2 n.lt_succ_self
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`.
This lemma proves this estimate assuming additionally that two of the spaces live in the same
universe, to make an induction possible. Use instead `norm_iteratedFDerivWithin_comp_le` that
removes this assumption. -/
theorem norm_iteratedFDerivWithin_comp_le_aux {Fu Gu : Type u} [NormedAddCommGroup Fu]
    [NormedSpace 𝕜 Fu] [NormedAddCommGroup Gu] [NormedSpace 𝕜 Gu] {g : Fu → Gu} {f : E → Fu} {n : ℕ}
    {s : Set E} {t : Set Fu} {x : E} (hg : ContDiffOn 𝕜 n g t) (hf : ContDiffOn 𝕜 n f s)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We argue by induction on `n`, using that `D^(n+1) (g ∘ f) = D^n (g ' ∘ f ⬝ f')`. The successive
    derivatives of `g' ∘ f` are controlled thanks to the inductive assumption, and those of `f'` are
    controlled by assumption.
    As composition of linear maps is a bilinear map, one may use
    `ContinuousLinearMap.norm_iteratedFDeriv_le_of_bilinear_of_le_one` to get from these a bound
    on `D^n (g ' ∘ f ⬝ f')`. -/
  induction' n using Nat.case_strong_induction_on with n IH generalizing Gu
  · simpa [norm_iteratedFDerivWithin_zero, Nat.factorial_zero, algebraMap.coe_one, one_mul,
      pow_zero, mul_one, comp_apply] using hC 0 le_rfl
  have M : (n : ℕ∞) < n.succ := Nat.cast_lt.2 n.lt_succ_self
  

Proof state:
case hi
𝕜 : Type u_1
inst✝¹² : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝¹¹ : NormedAddCommGroup D✝
inst✝¹⁰ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace 𝕜 E
F : Type uF
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace 𝕜 F
G : Type uG
inst✝⁵ : NormedAddCommGroup G
inst✝⁴ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
Fu : Type u
inst✝³ : NormedAddCommGroup Fu
inst✝² : NormedSpace 𝕜 Fu
f : E → Fu
s : Set E
t : Set Fu
x : E
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
n : ℕ
IH :
  ∀ m ≤ n,
    ∀ {Gu : Type u} [inst : NormedAddCommGroup Gu] [inst_1 : NormedSpace 𝕜 Gu] {g : Fu → Gu},
      ContDiffOn 𝕜 (↑m) g t →
        ContDiffOn 𝕜 (↑m) f s →
          (∀ i ≤ m, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C) →
            (∀ (i : ℕ), 1 ≤ i → i ≤ m → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) →
              ‖iteratedFDerivWithin 𝕜 m (g ∘ f) s x‖ ≤ ↑m ! * C * D ^ m
Gu : Type u
inst✝¹ : NormedAddCommGroup Gu
inst✝ : NormedSpace 𝕜 Gu
g : Fu → Gu
hg : ContDiffOn 𝕜 (↑(Nat.succ n)) g t
hf : ContDiffOn 𝕜 (↑(Nat.succ n)) f s
hC : ∀ i ≤ Nat.succ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ Nat.succ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
M : ↑n < ↑(Nat.succ n)
⊢ ‖iteratedFDerivWithin 𝕜 (Nat.succ n) (g ∘ f) s x‖ ≤ ↑(Nat.succ n)! * C * D ^ Nat.succ n

Next tactic:
have Cnonneg : 0 ≤ C := (norm_nonneg _).trans (hC 0 bot_le)
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
let Fu : Type max uF uG := ULift.{uG, uF} F
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
let Gu : Type max uF uG := ULift.{uF, uG} G
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  let Gu : Type max uF uG := ULift.{uF, uG} G
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
Gu : Type (max uF uG) := ULift.{uF, uG} G
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
have isoF : Fu ≃ₗᵢ[𝕜] F := LinearIsometryEquiv.ulift 𝕜 F
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  let Gu : Type max uF uG := ULift.{uF, uG} G
  have isoF : Fu ≃ₗᵢ[𝕜] F := LinearIsometryEquiv.ulift 𝕜 F
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
Gu : Type (max uF uG) := ULift.{uF, uG} G
isoF : Fu ≃ₗᵢ[𝕜] F
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
have isoG : Gu ≃ₗᵢ[𝕜] G := LinearIsometryEquiv.ulift 𝕜 G
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  let Gu : Type max uF uG := ULift.{uF, uG} G
  have isoF : Fu ≃ₗᵢ[𝕜] F := LinearIsometryEquiv.ulift 𝕜 F
  have isoG : Gu ≃ₗᵢ[𝕜] G := LinearIsometryEquiv.ulift 𝕜 G
  -- lift `f` and `g` to versions `fu` and `gu` on the lifted spaces.
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
Gu : Type (max uF uG) := ULift.{uF, uG} G
isoF : Fu ≃ₗᵢ[𝕜] F
isoG : Gu ≃ₗᵢ[𝕜] G
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
let fu : E → Fu := isoF.symm ∘ f
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  let Gu : Type max uF uG := ULift.{uF, uG} G
  have isoF : Fu ≃ₗᵢ[𝕜] F := LinearIsometryEquiv.ulift 𝕜 F
  have isoG : Gu ≃ₗᵢ[𝕜] G := LinearIsometryEquiv.ulift 𝕜 G
  -- lift `f` and `g` to versions `fu` and `gu` on the lifted spaces.
  let fu : E → Fu := isoF.symm ∘ f
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
Gu : Type (max uF uG) := ULift.{uF, uG} G
isoF : Fu ≃ₗᵢ[𝕜] F
isoG : Gu ≃ₗᵢ[𝕜] G
fu : E → Fu := ⇑(LinearIsometryEquiv.symm isoF) ∘ f
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
let gu : Fu → Gu := isoG.symm ∘ g ∘ isoF
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  let Gu : Type max uF uG := ULift.{uF, uG} G
  have isoF : Fu ≃ₗᵢ[𝕜] F := LinearIsometryEquiv.ulift 𝕜 F
  have isoG : Gu ≃ₗᵢ[𝕜] G := LinearIsometryEquiv.ulift 𝕜 G
  -- lift `f` and `g` to versions `fu` and `gu` on the lifted spaces.
  let fu : E → Fu := isoF.symm ∘ f
  let gu : Fu → Gu := isoG.symm ∘ g ∘ isoF
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
Gu : Type (max uF uG) := ULift.{uF, uG} G
isoF : Fu ≃ₗᵢ[𝕜] F
isoG : Gu ≃ₗᵢ[𝕜] G
fu : E → Fu := ⇑(LinearIsometryEquiv.symm isoF) ∘ f
gu : Fu → Gu := ⇑(LinearIsometryEquiv.symm isoG) ∘ g ∘ ⇑isoF
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
let tu := isoF ⁻¹' t
/-- If the derivatives within a set of `g` at `f x` are bounded by `C`, and the `i`-th derivative
within a set of `f` at `x` is bounded by `D^i` for all `1 ≤ i ≤ n`, then the `n`-th derivative
of `g ∘ f` is bounded by `n! * C * D^n`. -/
theorem norm_iteratedFDerivWithin_comp_le {g : F → G} {f : E → F} {n : ℕ} {s : Set E} {t : Set F}
    {x : E} {N : ℕ∞} (hg : ContDiffOn 𝕜 N g t) (hf : ContDiffOn 𝕜 N f s) (hn : (n : ℕ∞) ≤ N)
    (ht : UniqueDiffOn 𝕜 t) (hs : UniqueDiffOn 𝕜 s) (hst : MapsTo f s t) (hx : x ∈ s) {C : ℝ}
    {D : ℝ} (hC : ∀ i, i ≤ n → ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C)
    (hD : ∀ i, 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i) :
    ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ n ! * C * D ^ n := by
  /- We reduce the bound to the case where all spaces live in the same universe (in which we
    already have proved the result), by using linear isometries between the spaces and their `ULift`
    to a common universe. These linear isometries preserve the norm of the iterated derivative. -/
  let Fu : Type max uF uG := ULift.{uG, uF} F
  let Gu : Type max uF uG := ULift.{uF, uG} G
  have isoF : Fu ≃ₗᵢ[𝕜] F := LinearIsometryEquiv.ulift 𝕜 F
  have isoG : Gu ≃ₗᵢ[𝕜] G := LinearIsometryEquiv.ulift 𝕜 G
  -- lift `f` and `g` to versions `fu` and `gu` on the lifted spaces.
  let fu : E → Fu := isoF.symm ∘ f
  let gu : Fu → Gu := isoG.symm ∘ g ∘ isoF
  let tu := isoF ⁻¹' t
  

Proof state:
𝕜 : Type u_1
inst✝⁸ : NontriviallyNormedField 𝕜
D✝ : Type uD
inst✝⁷ : NormedAddCommGroup D✝
inst✝⁶ : NormedSpace 𝕜 D✝
E : Type uE
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
F : Type uF
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
G : Type uG
inst✝¹ : NormedAddCommGroup G
inst✝ : NormedSpace 𝕜 G
s✝ s₁ t✝ u : Set E
g : F → G
f : E → F
n : ℕ
s : Set E
t : Set F
x : E
N : ℕ∞
hg : ContDiffOn 𝕜 N g t
hf : ContDiffOn 𝕜 N f s
hn : ↑n ≤ N
ht : UniqueDiffOn 𝕜 t
hs : UniqueDiffOn 𝕜 s
hst : MapsTo f s t
hx : x ∈ s
C D : ℝ
hC : ∀ i ≤ n, ‖iteratedFDerivWithin 𝕜 i g t (f x)‖ ≤ C
hD : ∀ (i : ℕ), 1 ≤ i → i ≤ n → ‖iteratedFDerivWithin 𝕜 i f s x‖ ≤ D ^ i
Fu : Type (max uF uG) := ULift.{uG, uF} F
Gu : Type (max uF uG) := ULift.{uF, uG} G
isoF : Fu ≃ₗᵢ[𝕜] F
isoG : Gu ≃ₗᵢ[𝕜] G
fu : E → Fu := ⇑(LinearIsometryEquiv.symm isoF) ∘ f
gu : Fu → Gu := ⇑(LinearIsometryEquiv.symm isoG) ∘ g ∘ ⇑isoF
tu : Set Fu := ⇑isoF ⁻¹' t
⊢ ‖iteratedFDerivWithin 𝕜 n (g ∘ f) s x‖ ≤ ↑n ! * C * D ^ n

Next tactic:
have htu : UniqueDiffOn 𝕜 tu := isoF.toContinuousLinearEquiv.uniqueDiffOn_preimage_iff.2 ht