l3lab/ntp-mathlib huggingface dataset:
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
⊢ ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => f n x) atTop (𝓝 l)

Next tactic:
have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
⊢ ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x

Next tactic:
have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h1 : ∀ (n : ℕ), snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' (i : ℕ), B i
⊢ ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x

Next tactic:
have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h1 : ∀ (n : ℕ), snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' (i : ℕ), B i
h2 : ∀ (n : ℕ), ∫⁻ (a : α), (∑ i in Finset.range (n + 1), ↑‖f (i + 1) a - f i a‖₊) ^ p ∂μ ≤ (∑' (i : ℕ), B i) ^ p
⊢ ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x

Next tactic:
have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h1 : ∀ (n : ℕ), snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' (i : ℕ), B i
h2 : ∀ (n : ℕ), ∫⁻ (a : α), (∑ i in Finset.range (n + 1), ↑‖f (i + 1) a - f i a‖₊) ^ p ∂μ ≤ (∑' (i : ℕ), B i) ^ p
h3 : (∫⁻ (a : α), (∑' (i : ℕ), ↑‖f (i + 1) a - f i a‖₊) ^ p ∂μ) ^ (1 / p) ≤ ∑' (i : ℕ), B i
⊢ ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x

Next tactic:
have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h1 : ∀ (n : ℕ), snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' (i : ℕ), B i
h2 : ∀ (n : ℕ), ∫⁻ (a : α), (∑ i in Finset.range (n + 1), ↑‖f (i + 1) a - f i a‖₊) ^ p ∂μ ≤ (∑' (i : ℕ), B i) ^ p
h3 : (∫⁻ (a : α), (∑' (i : ℕ), ↑‖f (i + 1) a - f i a‖₊) ^ p ∂μ) ^ (1 / p) ≤ ∑' (i : ℕ), B i
h4 : ∀ᵐ (x : α) ∂μ, ∑' (i : ℕ), ↑‖f (i + 1) x - f i x‖₊ < ⊤
⊢ ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x

Next tactic:
exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
⊢ ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => f n x) atTop (𝓝 l)

Next tactic:
have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    refine' h_summable.mono fun x hx => _
    let hx_sum := hx.hasSum.tendsto_sum_nat
    exact ⟨∑' i, (f (i + 1) x - f i x), hx_sum⟩
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
⊢ ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)

Next tactic:
refine' h_summable.mono fun x hx => _
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    refine' h_summable.mono fun x hx => _
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
x : α
hx : Summable fun i => f (i + 1) x - f i x
⊢ ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)

Next tactic:
let hx_sum := hx.hasSum.tendsto_sum_nat
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    refine' h_summable.mono fun x hx => _
    let hx_sum := hx.hasSum.tendsto_sum_nat
    

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
x : α
hx : Summable fun i => f (i + 1) x - f i x
hx_sum : Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop
  (𝓝 (∑' (b : ℕ), (f (b + 1) x - f b x))) :=
  HasSum.tendsto_sum_nat (Summable.hasSum hx)
⊢ ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)

Next tactic:
exact ⟨∑' i, (f (i + 1) x - f i x), hx_sum⟩
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    refine' h_summable.mono fun x hx => _
    let hx_sum := hx.hasSum.tendsto_sum_nat
    exact ⟨∑' i, (f (i + 1) x - f i x), hx_sum⟩
  

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
h : ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)
⊢ ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => f n x) atTop (𝓝 l)

Next tactic:
refine' h.mono fun x hx => _
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    refine' h_summable.mono fun x hx => _
    let hx_sum := hx.hasSum.tendsto_sum_nat
    exact ⟨∑' i, (f (i + 1) x - f i x), hx_sum⟩
  refine' h.mono fun x hx => _
  

Proof state:
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
h : ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)
x : α
hx : ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)
⊢ ∃ l, Tendsto (fun n => f n x) atTop (𝓝 l)

Next tactic:
cases' hx with l hx
theorem ae_tendsto_of_cauchy_snorm' [CompleteSpace E] {f : ℕ → α → E} {p : ℝ}
    (hf : ∀ n, AEStronglyMeasurable (f n) μ) (hp1 : 1 ≤ p) {B : ℕ → ℝ≥0∞} (hB : ∑' i, B i ≠ ∞)
    (h_cau : ∀ N n m : ℕ, N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N) :
    ∀ᵐ x ∂μ, ∃ l : E, atTop.Tendsto (fun n => f n x) (𝓝 l) := by
  have h_summable : ∀ᵐ x ∂μ, Summable fun i : ℕ => f (i + 1) x - f i x := by
    have h1 :
      ∀ n, snorm' (fun x => ∑ i in Finset.range (n + 1), ‖f (i + 1) x - f i x‖) p μ ≤ ∑' i, B i :=
      snorm'_sum_norm_sub_le_tsum_of_cauchy_snorm' hf hp1 h_cau
    have h2 :
      ∀ n,
        (∫⁻ a, (∑ i in Finset.range (n + 1), ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ≤
          (∑' i, B i) ^ p :=
      fun n => lintegral_rpow_sum_coe_nnnorm_sub_le_rpow_tsum hp1 n (h1 n)
    have h3 : (∫⁻ a, (∑' i, ‖f (i + 1) a - f i a‖₊ : ℝ≥0∞) ^ p ∂μ) ^ (1 / p) ≤ ∑' i, B i :=
      lintegral_rpow_tsum_coe_nnnorm_sub_le_tsum hf hp1 h2
    have h4 : ∀ᵐ x ∂μ, (∑' i, ‖f (i + 1) x - f i x‖₊ : ℝ≥0∞) < ∞ :=
      tsum_nnnorm_sub_ae_lt_top hf hp1 hB h3
    exact h4.mono fun x hx => .of_nnnorm <| ENNReal.tsum_coe_ne_top_iff_summable.mp hx.ne
  have h :
    ∀ᵐ x ∂μ, ∃ l : E,
      atTop.Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) (𝓝 l) := by
    refine' h_summable.mono fun x hx => _
    let hx_sum := hx.hasSum.tendsto_sum_nat
    exact ⟨∑' i, (f (i + 1) x - f i x), hx_sum⟩
  refine' h.mono fun x hx => _
  cases' hx with l hx
  

Proof state:
case intro
α : Type u_1
E : Type u_2
F : Type u_3
G : Type u_4
m m0 : MeasurableSpace α
p✝ : ℝ≥0∞
q : ℝ
μ ν : Measure α
inst✝³ : NormedAddCommGroup E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedAddCommGroup G
inst✝ : CompleteSpace E
f : ℕ → α → E
p : ℝ
hf : ∀ (n : ℕ), AEStronglyMeasurable (f n) μ
hp1 : 1 ≤ p
B : ℕ → ℝ≥0∞
hB : ∑' (i : ℕ), B i ≠ ⊤
h_cau : ∀ (N n m : ℕ), N ≤ n → N ≤ m → snorm' (f n - f m) p μ < B N
h_summable : ∀ᵐ (x : α) ∂μ, Summable fun i => f (i + 1) x - f i x
h : ∀ᵐ (x : α) ∂μ, ∃ l, Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)
x : α
l : E
hx : Tendsto (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) atTop (𝓝 l)
⊢ ∃ l, Tendsto (fun n => f n x) atTop (𝓝 l)

Next tactic:
have h_rw_sum :
      (fun n => ∑ i in Finset.range n, (f (i + 1) x - f i x)) = fun n => f n x - f 0 x := by
    ext1 n
    change
      (∑ i : ℕ in Finset.range n, ((fun m => f m x) (i + 1) - (fun m => f m x) i)) = f n x - f 0 x
    rw [Finset.sum_range_sub (fun m => f m x)]