Theorem: MeasureTheory.Measure.QuasiMeasurePreserving.limsup_preimage_iterate_ae_eq
File: Mathlib/MeasureTheory/Measure/MeasureSpace.lean

tactic: intro n
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
⊢ ∀ (n : ℕ), (preimage f)^[n] s =ᵐ[μ] s
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
n : ℕ
⊢ (preimage f)^[n] s =ᵐ[μ] s

tactic: induction' n with n ih
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
n : ℕ
⊢ (preimage f)^[n] s =ᵐ[μ] s
state_after: case zero
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
⊢ (preimage f)^[0] s =ᵐ[μ] s

case succ
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
n : ℕ
ih : (preimage f)^[n] s =ᵐ[μ] s
⊢ (preimage f)^[n + 1] s =ᵐ[μ] s

tactic: simpa only [iterate_succ', comp_apply] using ae_eq_trans (hf.ae_eq ih) hs
state_before: case succ
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
n : ℕ
ih : (preimage f)^[n] s =ᵐ[μ] s
⊢ (preimage f)^[n + 1] s =ᵐ[μ] s
state_after: no goals

tactic: rfl
state_before: case zero
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Type u_5
R : Type u_6
R' : Type u_7
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s s' t : Set α
f✝¹ : α → β
μa μa' : Measure α
μb μb' : Measure β
μc : Measure γ
f✝ : α → β
f : α → α
hf : QuasiMeasurePreserving f μ μ
hs : f ⁻¹' s =ᵐ[μ] s
⊢ (preimage f)^[0] s =ᵐ[μ] s
state_after: no goals