Theorem: MeasureTheory.Measure.InnerRegularWRT.map
File: Mathlib/MeasureTheory/Measure/Regular.lean

Proof steps:
state_before: α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
⊢ (map f μ).InnerRegularWRT pb qb
state_after: α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < (map f μ) U
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
tactic: intro U hU r hr
state_before: α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < (map f μ) U
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
state_after: α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
tactic: rw [map_apply_of_aemeasurable hf (hB₂ _ hU)] at hr
state_before: α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
state_after: case intro.intro.intro
α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
K : Set α
hKU : K ⊆ f ⁻¹' U
hKc : pa K
hK : r < μ K
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
tactic: rcases H (hAB U hU) r hr with ⟨K, hKU, hKc, hK⟩
state_before: case intro.intro.intro
α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
K : Set α
hKU : K ⊆ f ⁻¹' U
hKc : pa K
hK : r < μ K
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
state_after: case intro.intro.intro
α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
K : Set α
hKU : K ⊆ f ⁻¹' U
hKc : pa K
hK : r < μ K
⊢ r < (map f μ) (f '' K)
tactic: refine ⟨f '' K, image_subset_iff.2 hKU, hAB' _ hKc, ?_⟩
state_before: case intro.intro.intro
α✝ : Type u_1
m : MeasurableSpace α✝
μ✝ : Measure α✝
p q : Set α✝ → Prop
U✝ : Set α✝
ε : ℝ≥0∞
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
K : Set α
hKU : K ⊆ f ⁻¹' U
hKc : pa K
hK : r < μ K
⊢ r < (map f μ) (f '' K)
state_after: no goals
tactic: exact hK.trans_le (le_map_apply_image hf _)