Theorem: MeasureTheory.Memℒp.integral_indicator_norm_ge_le
File: Mathlib/MeasureTheory/Function/UniformIntegrable.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: have htendsto :
      ∀ᵐ x ∂μ, Tendsto (fun M : ℕ => { x | (M : ℝ) ≤ ‖f x‖₊ }.indicator f x) atTop (𝓝 0) :=
    univ_mem' (id fun x => tendsto_indicator_ge f x)
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: have hmeas : ∀ M : ℕ, AEStronglyMeasurable ({ x | (M : ℝ) ≤ ‖f x‖₊ }.indicator f) μ := by
    intro M
    apply hf.1.indicator
    apply StronglyMeasurable.measurableSet_le stronglyMeasurable_const
      hmeas.nnnorm.measurable.coe_nnreal_real.stronglyMeasurable
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: have hbound : HasFiniteIntegral (fun x => ‖f x‖) μ := by
    rw [memℒp_one_iff_integrable] at hf
    exact hf.norm.2
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : Tendsto (fun n => ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ) atTop (𝓝 0)
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: rw [ENNReal.tendsto_atTop_zero] at this
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: case intro
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ENNReal.ofReal ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: obtain ⟨M, hM⟩ := this (ENNReal.ofReal ε) (ENNReal.ofReal_pos.2 hε)
state_before: case intro
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ENNReal.ofReal ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: case intro
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: simp only [true_and_iff, zero_tsub, zero_le, sub_zero, zero_add, coe_nnnorm,
    Set.mem_Icc] at hM
state_before: case intro
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
⊢ ∃ M, ∫⁻ (x : α), ↑‖{x | M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: case intro
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
⊢ ∫⁻ (x : α), ↑‖{x | ↑M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
tactic: refine ⟨M, ?_⟩
state_before: case intro
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
⊢ ∫⁻ (x : α), ↑‖{x | ↑M ≤ ↑‖f x‖₊}.indicator f x‖₊ ∂μ ≤ ENNReal.ofReal ε
state_after: case h.e'_3.h.e'_4.h
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
x✝ : α
⊢ ↑‖{x | ↑M ≤ ↑‖f x‖₊}.indicator f x✝‖₊ = ENNReal.ofReal ‖{x | ↑M ≤ ‖f x‖₊}.indicator f x✝‖
tactic: convert hM M le_rfl
state_before: case h.e'_3.h.e'_4.h
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
x✝ : α
⊢ ↑‖{x | ↑M ≤ ↑‖f x‖₊}.indicator f x✝‖₊ = ENNReal.ofReal ‖{x | ↑M ≤ ‖f x‖₊}.indicator f x✝‖
state_after: case h.e'_3.h.e'_4.h
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
x✝ : α
⊢ ↑‖{x | ↑M ≤ ‖f x‖}.indicator f x✝‖₊ = ↑⟨‖{x | ↑M ≤ ‖f x‖₊}.indicator f x✝‖, ⋯⟩
tactic: simp only [coe_nnnorm, ENNReal.ofReal_eq_coe_nnreal (norm_nonneg _)]
state_before: case h.e'_3.h.e'_4.h
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
μ : Measure α
inst✝ : NormedAddCommGroup β
p : ℝ≥0∞
f : α → β
hf : Memℒp f 1 μ
hmeas✝ : StronglyMeasurable f
ε : ℝ
hε : 0 < ε
htendsto : ∀ᵐ (x : α) ∂μ, Tendsto (fun M => {x | ↑M ≤ ↑‖f x‖₊}.indicator f x) atTop (𝓝 0)
hmeas : ∀ (M : ℕ), AEStronglyMeasurable ({x | ↑M ≤ ↑‖f x‖₊}.indicator f) μ
hbound : HasFiniteIntegral (fun x => ‖f x‖) μ
this : ∀ ε > 0, ∃ N, ∀ n ≥ N, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a - 0‖ ∂μ ≤ ε
M : ℕ
hM : ∀ n ≥ M, ∫⁻ (a : α), ENNReal.ofReal ‖{x | ↑n ≤ ‖f x‖₊}.indicator f a‖ ∂μ ≤ ENNReal.ofReal ε
x✝ : α
⊢ ↑‖{x | ↑M ≤ ‖f x‖}.indicator f x✝‖₊ = ↑⟨‖{x | ↑M ≤ ‖f x‖₊}.indicator f x✝‖, ⋯⟩
state_after: no goals
tactic: rfl