Theorem: MeasureTheory.Measure.isFiniteMeasure_map
File: Mathlib/MeasureTheory/Measure/Typeclasses.lean

tactic: by_cases hf : AEMeasurable f μ
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
⊢ IsFiniteMeasure (map f μ)
state_after: case pos
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : AEMeasurable f μ
⊢ IsFiniteMeasure (map f μ)

case neg
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : ¬AEMeasurable f μ
⊢ IsFiniteMeasure (map f μ)

tactic: constructor
state_before: case pos
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : AEMeasurable f μ
⊢ IsFiniteMeasure (map f μ)
state_after: case pos.measure_univ_lt_top
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : AEMeasurable f μ
⊢ (map f μ) univ < ⊤

tactic: rw [map_apply_of_aemeasurable hf MeasurableSet.univ]
state_before: case pos.measure_univ_lt_top
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : AEMeasurable f μ
⊢ (map f μ) univ < ⊤
state_after: case pos.measure_univ_lt_top
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : AEMeasurable f μ
⊢ μ (f ⁻¹' univ) < ⊤

tactic: exact measure_lt_top μ _
state_before: case pos.measure_univ_lt_top
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : AEMeasurable f μ
⊢ μ (f ⁻¹' univ) < ⊤
state_after: no goals

tactic: rw [map_of_not_aemeasurable hf]
state_before: case neg
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : ¬AEMeasurable f μ
⊢ IsFiniteMeasure (map f μ)
state_after: case neg
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : ¬AEMeasurable f μ
⊢ IsFiniteMeasure 0

tactic: exact MeasureTheory.isFiniteMeasureZero
state_before: case neg
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsFiniteMeasure μ
f : α → β
hf : ¬AEMeasurable f μ
⊢ IsFiniteMeasure 0
state_after: no goals