l3lab/ntp-mathlib huggingface dataset:
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · 

Proof state:
case h₁
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ ‖f (x + y) - f x - L₂ (x + y - x)‖ ≤ ε * r

Next tactic:
apply le_of_mem_A h₂
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · 

Proof state:
case h₁.hy
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ x ∈ closedBall x (r / 2)

Next tactic:
simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · 

Proof state:
case h₁.hz
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ x + y ∈ closedBall x (r / 2)

Next tactic:
simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
      · 

Proof state:
case h₂
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ ‖f (x + y) - f x - L₁ (x + y - x)‖ ≤ ε * r

Next tactic:
apply le_of_mem_A h₁
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
      · apply le_of_mem_A h₁
        · 

Proof state:
case h₂.hy
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ x ∈ closedBall x (r / 2)

Next tactic:
simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
      · apply le_of_mem_A h₁
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · 

Proof state:
case h₂.hz
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ x + y ∈ closedBall x (r / 2)

Next tactic:
simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
      · apply le_of_mem_A h₁
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
    _ = 2 * ε * r := by 

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ ε * r + ε * r = 2 * ε * r

Next tactic:
ring
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
      · apply le_of_mem_A h₁
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
    _ = 2 * ε * r := by ring
    _ ≤ 2 * ε * (2 * ‖c‖ * ‖y‖) := (mul_le_mul_of_nonneg_left ley (mul_nonneg (by 

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ 0 ≤ 2

Next tactic:
norm_num
theorem norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E}
    {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε := by
  refine' op_norm_le_of_shell (half_pos hr) (by positivity) hc _
  intro y ley ylt
  rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley
  calc
    ‖(L₁ - L₂) y‖ = ‖f (x + y) - f x - L₂ (x + y - x) - (f (x + y) - f x - L₁ (x + y - x))‖ := by
      simp
    _ ≤ ‖f (x + y) - f x - L₂ (x + y - x)‖ + ‖f (x + y) - f x - L₁ (x + y - x)‖ := (norm_sub_le _ _)
    _ ≤ ε * r + ε * r := by
      apply add_le_add
      · apply le_of_mem_A h₂
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
      · apply le_of_mem_A h₁
        · simp only [le_of_lt (half_pos hr), mem_closedBall, dist_self]
        · simp only [dist_eq_norm, add_sub_cancel', mem_closedBall, ylt.le]
    _ = 2 * ε * r := by ring
    _ ≤ 2 * ε * (2 * ‖c‖ * ‖y‖) := (mul_le_mul_of_nonneg_left ley (mul_nonneg (by norm_num) hε.le))
    _ = 4 * ‖c‖ * ε * ‖y‖ := by 

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
c : 𝕜
hc : 1 < ‖c‖
r ε : ℝ
hε : 0 < ε
hr : 0 < r
x : E
L₁ L₂ : E →L[𝕜] F
h₁ : x ∈ A f L₁ r ε
h₂ : x ∈ A f L₂ r ε
y : E
ley : r ≤ 2 * ‖c‖ * ‖y‖
ylt : ‖y‖ < r / 2
⊢ 2 * ε * (2 * ‖c‖ * ‖y‖) = 4 * ‖c‖ * ε * ‖y‖

Next tactic:
ring
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
⊢ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K} ⊆ D f K

Next tactic:
intro x hx
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
⊢ x ∈ D f K

Next tactic:
rw [D, mem_iInter]
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
⊢ ∀ (i : ℕ), x ∈ ⋃ n, ⋂ p, ⋂ (_ : p ≥ n), ⋂ q, ⋂ (_ : q ≥ n), B f K ((1 / 2) ^ p) ((1 / 2) ^ q) ((1 / 2) ^ i)

Next tactic:
intro e
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
⊢ x ∈ ⋃ n, ⋂ p, ⋂ (_ : p ≥ n), ⋂ q, ⋂ (_ : q ≥ n), B f K ((1 / 2) ^ p) ((1 / 2) ^ q) ((1 / 2) ^ e)

Next tactic:
have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by 

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
⊢ 0 < 1 / 2

Next tactic:
norm_num
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
⊢ x ∈ ⋃ n, ⋂ p, ⋂ (_ : p ≥ n), ⋂ q, ⋂ (_ : q ≥ n), B f K ((1 / 2) ^ p) ((1 / 2) ^ q) ((1 / 2) ^ e)

Next tactic:
rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  

Proof state:
case intro.intro
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
⊢ x ∈ ⋃ n, ⋂ p, ⋂ (_ : p ≥ n), ⋂ q, ⋂ (_ : q ≥ n), B f K ((1 / 2) ^ p) ((1 / 2) ^ q) ((1 / 2) ^ e)

Next tactic:
obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ) / 2 < 1)
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by 

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
⊢ 1 / 2 < 1

Next tactic:
norm_num
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ) / 2 < 1)
  

Proof state:
case intro.intro.intro
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
n : ℕ
hn : (1 / 2) ^ n < R
⊢ x ∈ ⋃ n, ⋂ p, ⋂ (_ : p ≥ n), ⋂ q, ⋂ (_ : q ≥ n), B f K ((1 / 2) ^ p) ((1 / 2) ^ q) ((1 / 2) ^ e)

Next tactic:
simp only [mem_iUnion, mem_iInter, B, mem_inter_iff]
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ) / 2 < 1)
  simp only [mem_iUnion, mem_iInter, B, mem_inter_iff]
  

Proof state:
case intro.intro.intro
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
n : ℕ
hn : (1 / 2) ^ n < R
⊢ ∃ i,
    ∀ i_1 ≥ i,
      ∀ i_3 ≥ i, ∃ i, ∃ (_ : i ∈ K), x ∈ A f i ((1 / 2) ^ i_1) ((1 / 2) ^ e) ∧ x ∈ A f i ((1 / 2) ^ i_3) ((1 / 2) ^ e)

Next tactic:
refine' ⟨n, fun p hp q hq => ⟨fderiv 𝕜 f x, hx.2, ⟨_, _⟩⟩⟩
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ) / 2 < 1)
  simp only [mem_iUnion, mem_iInter, B, mem_inter_iff]
  refine' ⟨n, fun p hp q hq => ⟨fderiv 𝕜 f x, hx.2, ⟨_, _⟩⟩⟩ <;>
    · 

Proof state:
case intro.intro.intro.refine'_1
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
n : ℕ
hn : (1 / 2) ^ n < R
p : ℕ
hp : p ≥ n
q : ℕ
hq : q ≥ n
⊢ x ∈ A f (fderiv 𝕜 f x) ((1 / 2) ^ p) ((1 / 2) ^ e)

Next tactic:
refine' hR _ ⟨pow_pos (by norm_num) _, lt_of_le_of_lt _ hn⟩
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ) / 2 < 1)
  simp only [mem_iUnion, mem_iInter, B, mem_inter_iff]
  refine' ⟨n, fun p hp q hq => ⟨fderiv 𝕜 f x, hx.2, ⟨_, _⟩⟩⟩ <;>
    · refine' hR _ ⟨pow_pos (by 

Proof state:
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
n : ℕ
hn : (1 / 2) ^ n < R
p : ℕ
hp : p ≥ n
q : ℕ
hq : q ≥ n
⊢ 0 < 1 / 2

Next tactic:
norm_num
/-- Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`. -/
theorem differentiable_set_subset_D :
    { x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K } ⊆ D f K := by
  intro x hx
  rw [D, mem_iInter]
  intro e
  have : (0 : ℝ) < (1 / 2) ^ e := pow_pos (by norm_num) _
  rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩
  obtain ⟨n, hn⟩ : ∃ n : ℕ, (1 / 2) ^ n < R :=
    exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ) / 2 < 1)
  simp only [mem_iUnion, mem_iInter, B, mem_inter_iff]
  refine' ⟨n, fun p hp q hq => ⟨fderiv 𝕜 f x, hx.2, ⟨_, _⟩⟩⟩ <;>
    · refine' hR _ ⟨pow_pos (by norm_num) _, lt_of_le_of_lt _ hn⟩
      

Proof state:
case intro.intro.intro.refine'_1
𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
f : E → F
K : Set (E →L[𝕜] F)
x : E
hx : x ∈ {x | DifferentiableAt 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
e : ℕ
this : 0 < (1 / 2) ^ e
R : ℝ
R_pos : R > 0
hR : ∀ r ∈ Ioo 0 R, x ∈ A f (fderiv 𝕜 f x) r ((1 / 2) ^ e)
n : ℕ
hn : (1 / 2) ^ n < R
p : ℕ
hp : p ≥ n
q : ℕ
hq : q ≥ n
⊢ (1 / 2) ^ p ≤ (1 / 2) ^ n

Next tactic:
exact pow_le_pow_of_le_one (by norm_num) (by norm_num) (by assumption)