Theorem: MeasureTheory.Measure.measure_preimage_isMulLeftInvariant_eq_smul_of_hasCompactSupport
File: Mathlib/MeasureTheory/Measure/Haar/Unique.lean

Proof steps:
state_before: G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: obtain ⟨u, -, u_mem, u_lim⟩ : ∃ u, StrictAnti u ∧ (∀ (n : ℕ), u n ∈ Ioo 0 1)
    ∧ Tendsto u atTop (𝓝 0) := exists_seq_strictAnti_tendsto' (zero_lt_one : (0 : ℝ) < 1)
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: let v : ℕ → ℝ → ℝ := fun n x ↦ thickenedIndicator (u_mem n).1 ({1} : Set ℝ) x
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: have vf_cont n : Continuous ((v n) ∘ f) := by
    apply Continuous.comp (continuous_induced_dom.comp ?_) hf
    exact BoundedContinuousFunction.continuous (thickenedIndicator (u_mem n).left {1})
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 : Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ') atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: have I1 := I μ' (by infer_instance)
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 : Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ') atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: simp_rw [M] at I1
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: have J1 : ∫ (x : G), indicator {1} (fun _ ↦ (1 : ℝ)) (f x) ∂μ'
      = ∫ (x : G), indicator {1} (fun _ ↦ 1) (f x) ∂(haarScalarFactor μ' μ • μ) :=
    tendsto_nhds_unique I1 (I (haarScalarFactor μ' μ • μ) (by infer_instance))
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
J2 : (μ' (f ⁻¹' {1})).toReal = ((μ'.haarScalarFactor μ • μ) (f ⁻¹' {1})).toReal
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: have J2 : ENNReal.toReal (μ' (f ⁻¹' {1}))
      = ENNReal.toReal ((haarScalarFactor μ' μ • μ) (f ⁻¹' {1})) := by
    have : (fun x ↦ indicator {1} (fun _ ↦ (1 : ℝ)) (f x)) =
        (fun x ↦ indicator (f ⁻¹' {1}) (fun _ ↦ (1 : ℝ)) x) := by
      ext x
      exact (indicator_comp_right f (s := ({1} : Set ℝ)) (g := (fun _ ↦ (1 : ℝ))) (x := x)).symm
    have mf : MeasurableSet (f ⁻¹' {1}) := (isClosed_singleton.preimage hf).measurableSet
    simpa only [this, mf, integral_indicator_const, smul_eq_mul, mul_one, Pi.smul_apply,
      nnreal_smul_coe_apply, ENNReal.toReal_mul, ENNReal.coe_toReal] using J1
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
J2 : (μ' (f ⁻¹' {1})).toReal = ((μ'.haarScalarFactor μ • μ) (f ⁻¹' {1})).toReal
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
J2 : (μ' (f ⁻¹' {1})).toReal = ((μ'.haarScalarFactor μ • μ) (f ⁻¹' {1})).toReal
C : IsCompact (f ⁻¹' {1})
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: have C : IsCompact (f ⁻¹' {1}) := h'f.isCompact_preimage hf isClosed_singleton (by simp)
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
J2 : (μ' (f ⁻¹' {1})).toReal = ((μ'.haarScalarFactor μ • μ) (f ⁻¹' {1})).toReal
C : IsCompact (f ⁻¹' {1})
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
J2 : μ' (f ⁻¹' {1}) = (μ'.haarScalarFactor μ • μ) (f ⁻¹' {1})
C : IsCompact (f ⁻¹' {1})
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
tactic: rw [ENNReal.toReal_eq_toReal C.measure_lt_top.ne C.measure_lt_top.ne] at J2
state_before: case intro.intro.intro
G : Type u_1
inst✝⁷ : TopologicalSpace G
inst✝⁶ : Group G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : MeasurableSpace G
inst✝³ : BorelSpace G
μ' μ : Measure G
inst✝² : μ.IsHaarMeasure
inst✝¹ : IsFiniteMeasureOnCompacts μ'
inst✝ : μ'.IsMulLeftInvariant
f : G → ℝ
hf : Continuous f
h'f : HasCompactSupport f
u : ℕ → ℝ
u_mem : ∀ (n : ℕ), u n ∈ Ioo 0 1
u_lim : Tendsto u atTop (𝓝 0)
v : ℕ → ℝ → ℝ := fun n x => ↑((thickenedIndicator ⋯ {1}) x)
vf_cont : ∀ (n : ℕ), Continuous (v n ∘ f)
I :
  ∀ (ν : Measure G),
    IsFiniteMeasureOnCompacts ν →
      Tendsto (fun n => ∫ (x : G), v n (f x) ∂ν) atTop (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂ν))
M : ∀ (n : ℕ), ∫ (x : G), v n (f x) ∂μ' = ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ
I1 :
  Tendsto (fun n => ∫ (x : G), v n (f x) ∂μ'.haarScalarFactor μ • μ) atTop
    (𝓝 (∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'))
J1 :
  ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ' =
    ∫ (x : G), {1}.indicator (fun x => 1) (f x) ∂μ'.haarScalarFactor μ • μ
J2 : μ' (f ⁻¹' {1}) = (μ'.haarScalarFactor μ • μ) (f ⁻¹' {1})
C : IsCompact (f ⁻¹' {1})
⊢ μ' (f ⁻¹' {1}) = μ'.haarScalarFactor μ • μ (f ⁻¹' {1})
state_after: no goals
tactic: simpa using J2