Theorem: MeasureTheory.IsFundamentalDomain.absolutelyContinuous_map
File: Mathlib/MeasureTheory/Measure/Haar/Quotient.lean

Proof steps:
state_before: G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
⊢ map QuotientGroup.mk μ ≪ map QuotientGroup.mk (μ.restrict 𝓕)
state_after: G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
⊢ map π μ ≪ map π (μ.restrict 𝓕)
tactic: set π : G → G ⧸ Γ := QuotientGroup.mk
state_before: G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
⊢ map π μ ≪ map π (μ.restrict 𝓕)
state_after: G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
⊢ map π μ ≪ map π (μ.restrict 𝓕)
tactic: have meas_π : Measurable π := continuous_quotient_mk'.measurable
state_before: G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
⊢ map π μ ≪ map π (μ.restrict 𝓕)
state_after: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
⊢ ∀ ⦃s : Set (G ⧸ Γ)⦄, MeasurableSet s → (map π (μ.restrict 𝓕)) s = 0 → (map π μ) s = 0
tactic: apply AbsolutelyContinuous.mk
state_before: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
⊢ ∀ ⦃s : Set (G ⧸ Γ)⦄, MeasurableSet s → (map π (μ.restrict 𝓕)) s = 0 → (map π μ) s = 0
state_after: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : (map π (μ.restrict 𝓕)) s = 0
⊢ (map π μ) s = 0
tactic: intro s s_meas hs
state_before: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : (map π (μ.restrict 𝓕)) s = 0
⊢ (map π μ) s = 0
state_after: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : (μ.restrict 𝓕) (π ⁻¹' s) = 0
⊢ μ (π ⁻¹' s) = 0
tactic: rw [map_apply meas_π s_meas] at hs ⊢
state_before: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : (μ.restrict 𝓕) (π ⁻¹' s) = 0
⊢ μ (π ⁻¹' s) = 0
state_after: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : μ (π ⁻¹' s ∩ 𝓕) = 0
⊢ μ (π ⁻¹' s) = 0

case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : (μ.restrict 𝓕) (π ⁻¹' s) = 0
⊢ MeasurableSet (π ⁻¹' s)
tactic: rw [Measure.restrict_apply] at hs
state_before: case h
G : Type u_1
inst✝⁸ : Group G
inst✝⁷ : MeasurableSpace G
inst✝⁶ : TopologicalSpace G
inst✝⁵ : TopologicalGroup G
inst✝⁴ : BorelSpace G
μ : Measure G
Γ : Subgroup G
𝓕 : Set G
h𝓕 : IsFundamentalDomain (↥Γ.op) 𝓕 μ
inst✝³ : Countable ↥Γ
inst✝² : MeasurableSpace (G ⧸ Γ)
inst✝¹ : BorelSpace (G ⧸ Γ)
inst✝ : μ.IsMulRightInvariant
π : G → G ⧸ Γ := QuotientGroup.mk
meas_π : Measurable π
s : Set (G ⧸ Γ)
s_meas : MeasurableSet s
hs : (μ.restrict 𝓕) (π ⁻¹' s) = 0
⊢ MeasurableSet (π ⁻¹' s)
state_after: no goals
tactic: exact MeasurableSet.preimage s_meas meas_π