Theorem: ProbabilityTheory.strong_law_aux6
File: Mathlib/Probability/StrongLaw.lean

Proof steps:
state_before: Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
⊢ ∀ᵐ (ω : Ω), Tendsto (fun n => (∑ i ∈ range ⌊c ^ n⌋₊, X i ω) / ↑⌊c ^ n⌋₊) atTop (𝓝 (∫ (a : Ω), X 0 a))
state_after: Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
⊢ ∀ᵐ (ω : Ω), Tendsto (fun n => (∑ i ∈ range ⌊c ^ n⌋₊, X i ω) / ↑⌊c ^ n⌋₊) atTop (𝓝 (∫ (a : Ω), X 0 a))
tactic: have H : ∀ n : ℕ, (0 : ℝ) < ⌊c ^ n⌋₊ := by
    intro n
    refine zero_lt_one.trans_le ?_
    simp only [Nat.one_le_cast, Nat.one_le_floor_iff, one_le_pow_of_one_le c_one.le n]
state_before: Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
⊢ ∀ᵐ (ω : Ω), Tendsto (fun n => (∑ i ∈ range ⌊c ^ n⌋₊, X i ω) / ↑⌊c ^ n⌋₊) atTop (𝓝 (∫ (a : Ω), X 0 a))
state_after: case h
Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
ω : Ω
hω :
  (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) (↑i) ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
h'ω : (fun n => ∑ i ∈ range n, truncation (X i) (↑i) ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n => ↑n
⊢ Tendsto (fun n => (∑ i ∈ range ⌊c ^ n⌋₊, X i ω) / ↑⌊c ^ n⌋₊) atTop (𝓝 (∫ (a : Ω), X 0 a))
tactic: filter_upwards [strong_law_aux4 X hint hindep hident hnonneg c_one,
    strong_law_aux5 X hint hident hnonneg] with ω hω h'ω
state_before: case h
Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
ω : Ω
hω :
  (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) (↑i) ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
h'ω : (fun n => ∑ i ∈ range n, truncation (X i) (↑i) ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n => ↑n
⊢ Tendsto (fun n => (∑ i ∈ range ⌊c ^ n⌋₊, X i ω) / ↑⌊c ^ n⌋₊) atTop (𝓝 (∫ (a : Ω), X 0 a))
state_after: case h
Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
ω : Ω
hω :
  (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) (↑i) ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
h'ω : (fun n => ∑ i ∈ range n, truncation (X i) (↑i) ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n => ↑n
⊢ (fun x => (∑ i ∈ range ⌊c ^ x⌋₊, X i ω) / ↑⌊c ^ x⌋₊ - ∫ (a : Ω), X 0 a) =o[atTop] fun _x => 1
tactic: rw [← tendsto_sub_nhds_zero_iff, ← Asymptotics.isLittleO_one_iff ℝ]
state_before: case h
Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
ω : Ω
hω :
  (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) (↑i) ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
h'ω : (fun n => ∑ i ∈ range n, truncation (X i) (↑i) ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n => ↑n
⊢ (fun x => (∑ i ∈ range ⌊c ^ x⌋₊, X i ω) / ↑⌊c ^ x⌋₊ - ∫ (a : Ω), X 0 a) =o[atTop] fun _x => 1
state_after: case h
Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
ω : Ω
hω :
  (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) (↑i) ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
h'ω : (fun n => ∑ i ∈ range n, truncation (X i) (↑i) ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n => ↑n
L : (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, X i ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
⊢ (fun x => (∑ i ∈ range ⌊c ^ x⌋₊, X i ω) / ↑⌊c ^ x⌋₊ - ∫ (a : Ω), X 0 a) =o[atTop] fun _x => 1
tactic: have L : (fun n : ℕ => ∑ i ∈ range ⌊c ^ n⌋₊, X i ω - ⌊c ^ n⌋₊ * 𝔼[X 0]) =o[atTop] fun n =>
      (⌊c ^ n⌋₊ : ℝ) := by
    have A : Tendsto (fun n : ℕ => ⌊c ^ n⌋₊) atTop atTop :=
      tendsto_nat_floor_atTop.comp (tendsto_pow_atTop_atTop_of_one_lt c_one)
    convert hω.sub (h'ω.comp_tendsto A) using 1
    ext1 n
    simp only [Function.comp_apply, sub_sub_sub_cancel_left]
state_before: case h
Ω : Type u_1
inst✝¹ : MeasureSpace Ω
inst✝ : IsProbabilityMeasure ℙ
X : ℕ → Ω → ℝ
hint : Integrable (X 0) ℙ
hindep : Pairwise fun i j => IndepFun (X i) (X j) ℙ
hident : ∀ (i : ℕ), IdentDistrib (X i) (X 0) ℙ ℙ
hnonneg : ∀ (i : ℕ) (ω : Ω), 0 ≤ X i ω
c : ℝ
c_one : 1 < c
H : ∀ (n : ℕ), 0 < ↑⌊c ^ n⌋₊
ω : Ω
hω :
  (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, truncation (X i) (↑i) ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
h'ω : (fun n => ∑ i ∈ range n, truncation (X i) (↑i) ω - ∑ i ∈ range n, X i ω) =o[atTop] fun n => ↑n
L : (fun n => ∑ i ∈ range ⌊c ^ n⌋₊, X i ω - ↑⌊c ^ n⌋₊ * ∫ (a : Ω), X 0 a) =o[atTop] fun n => ↑⌊c ^ n⌋₊
⊢ (fun x => (∑ i ∈ range ⌊c ^ x⌋₊, X i ω) / ↑⌊c ^ x⌋₊ - ∫ (a : Ω), X 0 a) =o[atTop] fun _x => 1
state_after: no goals
tactic: convert L.mul_isBigO (isBigO_refl (fun n : ℕ => (⌊c ^ n⌋₊ : ℝ)⁻¹) atTop) using 1 <;>
  (ext1 n; field_simp [(H n).ne'])