Theorem: MeasureTheory.withDensityᵥ_toReal
File: Mathlib/MeasureTheory/Measure/WithDensityVectorMeasure.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
⊢ (μ.withDensityᵥ fun x => (f x).toReal) = (μ.withDensity f).toSignedMeasure
state_after: α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
⊢ (μ.withDensityᵥ fun x => (f x).toReal) = (μ.withDensity f).toSignedMeasure
tactic: have hfi := integrable_toReal_of_lintegral_ne_top hfm hf
state_before: α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
⊢ (μ.withDensityᵥ fun x => (f x).toReal) = (μ.withDensity f).toSignedMeasure
state_after: α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
⊢ (μ.withDensityᵥ fun x => (f x).toReal) = (μ.withDensity f).toSignedMeasure
tactic: haveI := isFiniteMeasure_withDensity hf
state_before: α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
⊢ (μ.withDensityᵥ fun x => (f x).toReal) = (μ.withDensity f).toSignedMeasure
state_after: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ↑(μ.withDensityᵥ fun x => (f x).toReal) i = ↑(μ.withDensity f).toSignedMeasure i
tactic: ext i hi
state_before: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ↑(μ.withDensityᵥ fun x => (f x).toReal) i = ↑(μ.withDensity f).toSignedMeasure i
state_after: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ∀ᵐ (x : α) ∂μ.restrict i, f x < ⊤
tactic: rw [withDensityᵥ_apply hfi hi, toSignedMeasure_apply_measurable hi, withDensity_apply _ hi,
    integral_toReal hfm.restrict]
state_before: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ∀ᵐ (x : α) ∂μ.restrict i, f x < ⊤
state_after: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ∫⁻ (x : α) in i, f x ∂μ ≤ ∫⁻ (x : α), f x ∂μ
tactic: refine ae_lt_top' hfm.restrict (ne_top_of_le_ne_top hf ?_)
state_before: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ∫⁻ (x : α) in i, f x ∂μ ≤ ∫⁻ (x : α), f x ∂μ
state_after: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ∫⁻ (x : α) in i, f x ∂μ ≤ ∫⁻ (x : α) in Set.univ, f x ∂μ
tactic: conv_rhs => rw [← setLIntegral_univ]
state_before: case h
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ ν : Measure α
E : Type u_3
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℝ E
inst✝ : CompleteSpace E
f✝ g : α → E
f : α → ℝ≥0∞
hfm : AEMeasurable f μ
hf : ∫⁻ (x : α), f x ∂μ ≠ ⊤
hfi : Integrable (fun x => (f x).toReal) μ
this : IsFiniteMeasure (μ.withDensity f)
i : Set α
hi : MeasurableSet i
⊢ ∫⁻ (x : α) in i, f x ∂μ ≤ ∫⁻ (x : α) in Set.univ, f x ∂μ
state_after: no goals
tactic: exact lintegral_mono_set (Set.subset_univ _)