Theorem: MeasureTheory.AECover.iSup_lintegral_eq_of_countably_generated
File: Mathlib/MeasureTheory/Integral/IntegralEqImproper.lean

Proof steps:
state_before: α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
⊢ ⨆ i, ∫⁻ (x : α) in φ i, f x ∂μ = ∫⁻ (x : α), f x ∂μ
state_after: α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
⊢ ⨆ i, ∫⁻ (x : α) in φ i, f x ∂μ = ∫⁻ (x : α), f x ∂μ
tactic: have := hφ.lintegral_tendsto_of_countably_generated hfm
state_before: α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
⊢ ⨆ i, ∫⁻ (x : α) in φ i, f x ∂μ = ∫⁻ (x : α), f x ∂μ
state_after: α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
w : ℝ≥0∞
hw : w < ∫⁻ (x : α), f x ∂μ
⊢ ∃ i, w < ∫⁻ (x : α) in φ i, f x ∂μ
tactic: refine ciSup_eq_of_forall_le_of_forall_lt_exists_gt
    (fun i => lintegral_mono' Measure.restrict_le_self le_rfl) fun w hw => ?_
state_before: α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
w : ℝ≥0∞
hw : w < ∫⁻ (x : α), f x ∂μ
⊢ ∃ i, w < ∫⁻ (x : α) in φ i, f x ∂μ
state_after: case intro.intro
α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
w : ℝ≥0∞
hw : w < ∫⁻ (x : α), f x ∂μ
m : ℝ≥0∞
hm₁ : w < m
hm₂ : m < ∫⁻ (x : α), f x ∂μ
⊢ ∃ i, w < ∫⁻ (x : α) in φ i, f x ∂μ
tactic: rcases exists_between hw with ⟨m, hm₁, hm₂⟩
state_before: case intro.intro
α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
w : ℝ≥0∞
hw : w < ∫⁻ (x : α), f x ∂μ
m : ℝ≥0∞
hm₁ : w < m
hm₂ : m < ∫⁻ (x : α), f x ∂μ
⊢ ∃ i, w < ∫⁻ (x : α) in φ i, f x ∂μ
state_after: case intro.intro.intro
α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
w : ℝ≥0∞
hw : w < ∫⁻ (x : α), f x ∂μ
m : ℝ≥0∞
hm₁ : w < m
hm₂ : m < ∫⁻ (x : α), f x ∂μ
i : ι
hi : m ≤ ∫⁻ (x : α) in φ i, f x ∂μ
⊢ ∃ i, w < ∫⁻ (x : α) in φ i, f x ∂μ
tactic: rcases (eventually_ge_of_tendsto_gt hm₂ this).exists with ⟨i, hi⟩
state_before: case intro.intro.intro
α : Type u_1
ι : Type u_2
inst✝³ : MeasurableSpace α
μ : Measure α
l : Filter ι
inst✝² : Nonempty ι
inst✝¹ : l.NeBot
inst✝ : l.IsCountablyGenerated
φ : ι → Set α
hφ : AECover μ l φ
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
this : Tendsto (fun i => ∫⁻ (x : α) in φ i, f x ∂μ) l (𝓝 (∫⁻ (x : α), f x ∂μ))
w : ℝ≥0∞
hw : w < ∫⁻ (x : α), f x ∂μ
m : ℝ≥0∞
hm₁ : w < m
hm₂ : m < ∫⁻ (x : α), f x ∂μ
i : ι
hi : m ≤ ∫⁻ (x : α) in φ i, f x ∂μ
⊢ ∃ i, w < ∫⁻ (x : α) in φ i, f x ∂μ
state_after: no goals
tactic: exact ⟨i, lt_of_lt_of_le hm₁ hi⟩