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

Proof steps:
state_before: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
⊢ μ' s = μ'.haarScalarFactor μ • μ s
state_after: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
⊢ μ' s = μ'.haarScalarFactor μ • μ s
tactic: let c := haarScalarFactor μ' μ
state_before: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
⊢ μ' s = μ'.haarScalarFactor μ • μ s
state_after: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
⊢ μ' s = μ'.haarScalarFactor μ • μ s
tactic: have B : ∀ s, MeasurableSet s → μ s < ∞ → μ' s < ∞ → μ' s = (c • μ) s := by
    intro s s_meas hs h's
    have : (c • μ) s ≠ ∞ := by simp [ENNReal.mul_eq_top, hs.ne]
    rw [s_meas.measure_eq_iSup_isCompact_of_ne_top h's.ne,
        s_meas.measure_eq_iSup_isCompact_of_ne_top this]
    congr! 4 with K _Ks K_comp
    exact measure_isMulInvariant_eq_smul_of_isCompact_closure μ' μ K_comp.closure
state_before: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
⊢ μ' s = μ'.haarScalarFactor μ • μ s
state_after: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
⊢ μ' s = μ'.haarScalarFactor μ • μ s
tactic: let t := toMeasurable μ' s ∩ toMeasurable μ s
state_before: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
⊢ μ' s = μ'.haarScalarFactor μ • μ s
state_after: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
⊢ μ' s = μ'.haarScalarFactor μ • μ s
tactic: have st : s ⊆ t := subset_inter (subset_toMeasurable μ' s) (subset_toMeasurable μ s)
state_before: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
mu'_t : μ' t = μ' s
mu_t : μ t = μ s
⊢ μ' s = μ'.haarScalarFactor μ • μ s
state_after: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
mu'_t : μ' t = μ' s
mu_t : μ t = μ s
⊢ μ' t = ↑(μ'.haarScalarFactor μ) * μ t
tactic: simp only [← mu'_t, smul_toOuterMeasure, OuterMeasure.coe_smul, Pi.smul_apply, ← mu_t,
    nnreal_smul_coe_apply]
state_before: G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
mu'_t : μ' t = μ' s
mu_t : μ t = μ s
⊢ μ' t = ↑(μ'.haarScalarFactor μ) * μ t
state_after: case a
G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
mu'_t : μ' t = μ' s
mu_t : μ t = μ s
⊢ MeasurableSet t

case a
G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
mu'_t : μ' t = μ' s
mu_t : μ t = μ s
⊢ μ t < ⊤

case a
G : Type u_1
inst✝¹⁰ : TopologicalSpace G
inst✝⁹ : Group G
inst✝⁸ : TopologicalGroup G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : BorelSpace G
inst✝⁵ : LocallyCompactSpace G
μ' μ : Measure G
inst✝⁴ : μ.IsHaarMeasure
inst✝³ : IsFiniteMeasureOnCompacts μ'
inst✝² : μ'.IsMulLeftInvariant
inst✝¹ : μ.InnerRegularCompactLTTop
inst✝ : μ'.InnerRegularCompactLTTop
s : Set G
hs : μ s ≠ ⊤
h's : μ' s ≠ ⊤
c : ℝ≥0 := μ'.haarScalarFactor μ
B : ∀ (s : Set G), MeasurableSet s → μ s < ⊤ → μ' s < ⊤ → μ' s = (c • μ) s
t : Set G := toMeasurable μ' s ∩ toMeasurable μ s
st : s ⊆ t
mu'_t : μ' t = μ' s
mu_t : μ t = μ s
⊢ μ' t < ⊤
tactic: apply B