l3lab/ntp-mathlib huggingface dataset:
/-- If `f` is eventually differentiable along a nontrivial filter `l : Filter ℝ` that is generated
by convex sets, the norm of `f` tends to infinity along `l`, and `f' = O(g)` along `l`, where `f'`
is the derivative of `f`, then `g` is not integrable on any interval `a..b` such that
`[a, b] ∈ l`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_filter {f : ℝ → E} {g : ℝ → F}
    {a b : ℝ} (l : Filter ℝ) [NeBot l] [TendstoIxxClass Icc l l] (hl : [[a, b]] ∈ l)
    (hd : ∀ᶠ x in l, DifferentiableAt ℝ f x) (hf : Tendsto (fun x => ‖f x‖) l atTop)
    (hfg : deriv f =O[l] g) : ¬IntervalIntegrable g volume a b := by
  

Proof state:
E : Type u_1
F : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace ℝ E
inst✝² : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b : ℝ
l : Filter ℝ
inst✝¹ : NeBot l
inst✝ : TendstoIxxClass Icc l l
hl : [[a, b]] ∈ l
hd : ∀ᶠ (x : ℝ) in l, DifferentiableAt ℝ f x
hf : Tendsto (fun x => ‖f x‖) l atTop
hfg : deriv f =O[l] g
⊢ ¬IntervalIntegrable g volume a b

Next tactic:
rw [intervalIntegrable_iff']
/-- If `f` is eventually differentiable along a nontrivial filter `l : Filter ℝ` that is generated
by convex sets, the norm of `f` tends to infinity along `l`, and `f' = O(g)` along `l`, where `f'`
is the derivative of `f`, then `g` is not integrable on any interval `a..b` such that
`[a, b] ∈ l`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_filter {f : ℝ → E} {g : ℝ → F}
    {a b : ℝ} (l : Filter ℝ) [NeBot l] [TendstoIxxClass Icc l l] (hl : [[a, b]] ∈ l)
    (hd : ∀ᶠ x in l, DifferentiableAt ℝ f x) (hf : Tendsto (fun x => ‖f x‖) l atTop)
    (hfg : deriv f =O[l] g) : ¬IntervalIntegrable g volume a b := by
  rw [intervalIntegrable_iff']
  

Proof state:
E : Type u_1
F : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace ℝ E
inst✝² : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b : ℝ
l : Filter ℝ
inst✝¹ : NeBot l
inst✝ : TendstoIxxClass Icc l l
hl : [[a, b]] ∈ l
hd : ∀ᶠ (x : ℝ) in l, DifferentiableAt ℝ f x
hf : Tendsto (fun x => ‖f x‖) l atTop
hfg : deriv f =O[l] g
⊢ ¬IntegrableOn g [[a, b]]

Next tactic:
exact not_integrableOn_of_tendsto_norm_atTop_of_deriv_isBigO_filter _ hl hd hf hfg
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
⊢ ¬IntervalIntegrable g volume a b

Next tactic:
obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
    · refine' ⟨𝓝[>] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Ici_diff_left]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Ici ⟨hc.1, hlt⟩) _
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
⊢ ∃ l, TendstoIxxClass Icc l l ∧ NeBot l ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l

Next tactic:
cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · 

Proof state:
case inl
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
hlt : min a b < c
⊢ ∃ l, TendstoIxxClass Icc l l ∧ NeBot l ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l

Next tactic:
refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      

Proof state:
case inl
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
hlt : min a b < c
⊢ [[a, b]] \ {c} ∈ 𝓝[<] c

Next tactic:
rw [← Iic_diff_right]
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      

Proof state:
case inl
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
hlt : min a b < c
⊢ [[a, b]] \ {c} ∈ 𝓝[Iic c \ {c}] c

Next tactic:
exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
    · 

Proof state:
case inr
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
hlt : c < max a b
⊢ ∃ l, TendstoIxxClass Icc l l ∧ NeBot l ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l

Next tactic:
refine' ⟨𝓝[>] c, inferInstance, inferInstance, inf_le_left, _⟩
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
    · refine' ⟨𝓝[>] c, inferInstance, inferInstance, inf_le_left, _⟩
      

Proof state:
case inr
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
hlt : c < max a b
⊢ [[a, b]] \ {c} ∈ 𝓝[>] c

Next tactic:
rw [← Ici_diff_left]
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
    · refine' ⟨𝓝[>] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Ici_diff_left]
      

Proof state:
case inr
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
hlt : c < max a b
⊢ [[a, b]] \ {c} ∈ 𝓝[Ici c \ {c}] c

Next tactic:
exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Ici ⟨hc.1, hlt⟩) _
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
    · refine' ⟨𝓝[>] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Ici_diff_left]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Ici ⟨hc.1, hlt⟩) _
  

Proof state:
case intro.intro.intro.intro
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
l : Filter ℝ
hl : TendstoIxxClass Icc l l
hl' : NeBot l
hle : l ≤ 𝓝 c
hmem : [[a, b]] \ {c} ∈ l
⊢ ¬IntervalIntegrable g volume a b

Next tactic:
have : l ≤ 𝓝[[[a, b]] \ {c}] c := le_inf hle (le_principal_iff.2 hmem)
/-- If `a ≠ b`, `c ∈ [a, b]`, `f` is differentiable in the neighborhood of `c` within
`[a, b] \ {c}`, `‖f x‖ → ∞` as `x → c` within `[a, b] \ {c}`, and `f' = O(g)` along
`𝓝[[a, b] \ {c}] c`, where `f'` is the derivative of `f`, then `g` is not interval integrable on
`a..b`. -/
theorem not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_within_diff_singleton
    {f : ℝ → E} {g : ℝ → F} {a b c : ℝ} (hne : a ≠ b) (hc : c ∈ [[a, b]])
    (h_deriv : ∀ᶠ x in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x)
    (h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop)
    (hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g) : ¬IntervalIntegrable g volume a b := by
  obtain ⟨l, hl, hl', hle, hmem⟩ :
    ∃ l : Filter ℝ, TendstoIxxClass Icc l l ∧ l.NeBot ∧ l ≤ 𝓝 c ∧ [[a, b]] \ {c} ∈ l := by
    cases' (min_lt_max.2 hne).lt_or_lt c with hlt hlt
    · refine' ⟨𝓝[<] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Iic_diff_right]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Iic ⟨hlt, hc.2⟩) _
    · refine' ⟨𝓝[>] c, inferInstance, inferInstance, inf_le_left, _⟩
      rw [← Ici_diff_left]
      exact diff_mem_nhdsWithin_diff (Icc_mem_nhdsWithin_Ici ⟨hc.1, hlt⟩) _
  have : l ≤ 𝓝[[[a, b]] \ {c}] c := le_inf hle (le_principal_iff.2 hmem)
  

Proof state:
case intro.intro.intro.intro
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → E
g : ℝ → F
a b c : ℝ
hne : a ≠ b
hc : c ∈ [[a, b]]
h_deriv : ∀ᶠ (x : ℝ) in 𝓝[[[a, b]] \ {c}] c, DifferentiableAt ℝ f x
h_infty : Tendsto (fun x => ‖f x‖) (𝓝[[[a, b]] \ {c}] c) atTop
hg : deriv f =O[𝓝[[[a, b]] \ {c}] c] g
l : Filter ℝ
hl : TendstoIxxClass Icc l l
hl' : NeBot l
hle : l ≤ 𝓝 c
hmem : [[a, b]] \ {c} ∈ l
this : l ≤ 𝓝[[[a, b]] \ {c}] c
⊢ ¬IntervalIntegrable g volume a b

Next tactic:
exact not_intervalIntegrable_of_tendsto_norm_atTop_of_deriv_isBigO_filter l
    (mem_of_superset hmem (diff_subset _ _)) (h_deriv.filter_mono this) (h_infty.mono_left this)
    (hg.mono this)
/-- If `f` grows in the punctured neighborhood of `c : ℝ` at least as fast as `1 / (x - c)`,
then it is not interval integrable on any nontrivial interval `a..b`, `c ∈ [a, b]`. -/
theorem not_intervalIntegrable_of_sub_inv_isBigO_punctured {f : ℝ → F} {a b c : ℝ}
    (hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f) (hne : a ≠ b) (hc : c ∈ [[a, b]]) :
    ¬IntervalIntegrable f volume a b := by
  

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → F
a b c : ℝ
hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f
hne : a ≠ b
hc : c ∈ [[a, b]]
⊢ ¬IntervalIntegrable f volume a b

Next tactic:
have A : ∀ᶠ x in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x := by
    filter_upwards [self_mem_nhdsWithin] with x hx
    simpa using ((hasDerivAt_id x).sub_const c).log (sub_ne_zero.2 hx)
/-- If `f` grows in the punctured neighborhood of `c : ℝ` at least as fast as `1 / (x - c)`,
then it is not interval integrable on any nontrivial interval `a..b`, `c ∈ [a, b]`. -/
theorem not_intervalIntegrable_of_sub_inv_isBigO_punctured {f : ℝ → F} {a b c : ℝ}
    (hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f) (hne : a ≠ b) (hc : c ∈ [[a, b]]) :
    ¬IntervalIntegrable f volume a b := by
  have A : ∀ᶠ x in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x := by
    

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → F
a b c : ℝ
hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f
hne : a ≠ b
hc : c ∈ [[a, b]]
⊢ ∀ᶠ (x : ℝ) in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x

Next tactic:
filter_upwards [self_mem_nhdsWithin] with x hx
/-- If `f` grows in the punctured neighborhood of `c : ℝ` at least as fast as `1 / (x - c)`,
then it is not interval integrable on any nontrivial interval `a..b`, `c ∈ [a, b]`. -/
theorem not_intervalIntegrable_of_sub_inv_isBigO_punctured {f : ℝ → F} {a b c : ℝ}
    (hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f) (hne : a ≠ b) (hc : c ∈ [[a, b]]) :
    ¬IntervalIntegrable f volume a b := by
  have A : ∀ᶠ x in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x := by
    filter_upwards [self_mem_nhdsWithin] with x hx
    

Proof state:
case h
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → F
a b c : ℝ
hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f
hne : a ≠ b
hc : c ∈ [[a, b]]
x : ℝ
hx : x ∈ {c}ᶜ
⊢ HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x

Next tactic:
simpa using ((hasDerivAt_id x).sub_const c).log (sub_ne_zero.2 hx)
/-- If `f` grows in the punctured neighborhood of `c : ℝ` at least as fast as `1 / (x - c)`,
then it is not interval integrable on any nontrivial interval `a..b`, `c ∈ [a, b]`. -/
theorem not_intervalIntegrable_of_sub_inv_isBigO_punctured {f : ℝ → F} {a b c : ℝ}
    (hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f) (hne : a ≠ b) (hc : c ∈ [[a, b]]) :
    ¬IntervalIntegrable f volume a b := by
  have A : ∀ᶠ x in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x := by
    filter_upwards [self_mem_nhdsWithin] with x hx
    simpa using ((hasDerivAt_id x).sub_const c).log (sub_ne_zero.2 hx)
  

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → F
a b c : ℝ
hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f
hne : a ≠ b
hc : c ∈ [[a, b]]
A : ∀ᶠ (x : ℝ) in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x
⊢ ¬IntervalIntegrable f volume a b

Next tactic:
have B : Tendsto (fun x => ‖Real.log (x - c)‖) (𝓝[≠] c) atTop := by
    refine' tendsto_abs_atBot_atTop.comp (Real.tendsto_log_nhdsWithin_zero.comp _)
    rw [← sub_self c]
    exact ((hasDerivAt_id c).sub_const c).tendsto_punctured_nhds one_ne_zero
/-- If `f` grows in the punctured neighborhood of `c : ℝ` at least as fast as `1 / (x - c)`,
then it is not interval integrable on any nontrivial interval `a..b`, `c ∈ [a, b]`. -/
theorem not_intervalIntegrable_of_sub_inv_isBigO_punctured {f : ℝ → F} {a b c : ℝ}
    (hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f) (hne : a ≠ b) (hc : c ∈ [[a, b]]) :
    ¬IntervalIntegrable f volume a b := by
  have A : ∀ᶠ x in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x := by
    filter_upwards [self_mem_nhdsWithin] with x hx
    simpa using ((hasDerivAt_id x).sub_const c).log (sub_ne_zero.2 hx)
  have B : Tendsto (fun x => ‖Real.log (x - c)‖) (𝓝[≠] c) atTop := by
    

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → F
a b c : ℝ
hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f
hne : a ≠ b
hc : c ∈ [[a, b]]
A : ∀ᶠ (x : ℝ) in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x
⊢ Tendsto (fun x => ‖Real.log (x - c)‖) (𝓝[≠] c) atTop

Next tactic:
refine' tendsto_abs_atBot_atTop.comp (Real.tendsto_log_nhdsWithin_zero.comp _)
/-- If `f` grows in the punctured neighborhood of `c : ℝ` at least as fast as `1 / (x - c)`,
then it is not interval integrable on any nontrivial interval `a..b`, `c ∈ [a, b]`. -/
theorem not_intervalIntegrable_of_sub_inv_isBigO_punctured {f : ℝ → F} {a b c : ℝ}
    (hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f) (hne : a ≠ b) (hc : c ∈ [[a, b]]) :
    ¬IntervalIntegrable f volume a b := by
  have A : ∀ᶠ x in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x := by
    filter_upwards [self_mem_nhdsWithin] with x hx
    simpa using ((hasDerivAt_id x).sub_const c).log (sub_ne_zero.2 hx)
  have B : Tendsto (fun x => ‖Real.log (x - c)‖) (𝓝[≠] c) atTop := by
    refine' tendsto_abs_atBot_atTop.comp (Real.tendsto_log_nhdsWithin_zero.comp _)
    

Proof state:
E : Type u_1
F : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : NormedAddCommGroup F
f : ℝ → F
a b c : ℝ
hf : (fun x => (x - c)⁻¹) =O[𝓝[≠] c] f
hne : a ≠ b
hc : c ∈ [[a, b]]
A : ∀ᶠ (x : ℝ) in 𝓝[≠] c, HasDerivAt (fun x => Real.log (x - c)) (x - c)⁻¹ x
⊢ Tendsto (fun x => x - c) (𝓝[≠] c) (𝓝[≠] 0)

Next tactic:
rw [← sub_self c]