Theorem: MeasureTheory.intervalIntegral_tendsto_integral_Ioi
File: Mathlib/MeasureTheory/Integral/IntegralEqImproper.lean

Proof steps:
state_before: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
⊢ Tendsto (fun i => ∫ (x : ℝ) in a..b i, f x ∂μ) l (𝓝 (∫ (x : ℝ) in Ioi a, f x ∂μ))
state_after: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
⊢ Tendsto (fun i => ∫ (x : ℝ) in a..b i, f x ∂μ) l (𝓝 (∫ (x : ℝ) in Ioi a, f x ∂μ))
tactic: let φ i := Iic (b i)
state_before: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
⊢ Tendsto (fun i => ∫ (x : ℝ) in a..b i, f x ∂μ) l (𝓝 (∫ (x : ℝ) in Ioi a, f x ∂μ))
state_after: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
⊢ Tendsto (fun i => ∫ (x : ℝ) in a..b i, f x ∂μ) l (𝓝 (∫ (x : ℝ) in Ioi a, f x ∂μ))
tactic: have hφ : AECover (μ.restrict <| Ioi a) l φ := aecover_Iic hb
state_before: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
⊢ Tendsto (fun i => ∫ (x : ℝ) in a..b i, f x ∂μ) l (𝓝 (∫ (x : ℝ) in Ioi a, f x ∂μ))
state_after: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
⊢ (fun i => ∫ (x : ℝ) in φ i, f x ∂μ.restrict (Ioi a)) =ᶠ[l] fun i => ∫ (x : ℝ) in a..b i, f x ∂μ
tactic: refine (hφ.integral_tendsto_of_countably_generated hfi).congr' ?_
state_before: ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
⊢ (fun i => ∫ (x : ℝ) in φ i, f x ∂μ.restrict (Ioi a)) =ᶠ[l] fun i => ∫ (x : ℝ) in a..b i, f x ∂μ
state_after: case h
ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
i : ι
hbi : a ≤ b i
⊢ ∫ (x : ℝ) in φ i, f x ∂μ.restrict (Ioi a) = ∫ (x : ℝ) in a..b i, f x ∂μ
tactic: filter_upwards [hb.eventually (eventually_ge_atTop <| a)] with i hbi
state_before: case h
ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
i : ι
hbi : a ≤ b i
⊢ ∫ (x : ℝ) in φ i, f x ∂μ.restrict (Ioi a) = ∫ (x : ℝ) in a..b i, f x ∂μ
state_after: case h
ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
i : ι
hbi : a ≤ b i
⊢ ∫ (x : ℝ) in Ioi a ∩ φ i, f x ∂μ = ∫ (x : ℝ) in Ioc a (b i), f x ∂μ
tactic: rw [intervalIntegral.integral_of_le hbi, Measure.restrict_restrict (hφ.measurableSet i),
    inter_comm]
state_before: case h
ι : Type u_1
E : Type u_2
μ : Measure ℝ
l : Filter ι
inst✝³ : l.IsCountablyGenerated
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
a✝ b : ι → ℝ
f : ℝ → E
a : ℝ
hfi : IntegrableOn f (Ioi a) μ
hb : Tendsto b l atTop
φ : ι → Set ℝ := fun i => Iic (b i)
hφ : AECover (μ.restrict (Ioi a)) l φ
i : ι
hbi : a ≤ b i
⊢ ∫ (x : ℝ) in Ioi a ∩ φ i, f x ∂μ = ∫ (x : ℝ) in Ioc a (b i), f x ∂μ
state_after: no goals
tactic: rfl