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

Proof steps:
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
⊢ μ.InnerRegularWRT IsCompact IsClosed
state_after: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: intro F hF r hr
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: set B : ℕ → Set X := compactCovering X
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: have hBc : ∀ n, IsCompact (F ∩ B n) := fun n => (isCompact_compactCovering X n).inter_left hF
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: have hBU : ⋃ n, F ∩ B n = F := by rw [← inter_iUnion, iUnion_compactCovering, Set.inter_univ]
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
this : μ F = ⨆ n, μ (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: have : μ F = ⨆ n, μ (F ∩ B n) := by
    rw [← measure_iUnion_eq_iSup, hBU]
    exact Monotone.directed_le fun m n h => inter_subset_inter_right _ (compactCovering_subset _ h)
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
hr : r < μ F
B : ℕ → Set X := compactCovering X
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
this : μ F = ⨆ n, μ (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
B : ℕ → Set X := compactCovering X
hr : r < ⨆ n, μ (F ∩ B n)
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
this : μ F = ⨆ n, μ (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: rw [this] at hr
state_before: α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
B : ℕ → Set X := compactCovering X
hr : r < ⨆ n, μ (F ∩ B n)
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
this : μ F = ⨆ n, μ (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: case intro
α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
B : ℕ → Set X := compactCovering X
hr : r < ⨆ n, μ (F ∩ B n)
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
this : μ F = ⨆ n, μ (F ∩ B n)
n : ℕ
hn : r < μ (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
tactic: rcases lt_iSup_iff.1 hr with ⟨n, hn⟩
state_before: case intro
α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
μ✝ : Measure α
p q : Set α → Prop
U s : Set α
ε r✝ : ℝ≥0∞
X : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : SigmaCompactSpace X
inst✝ : MeasurableSpace X
μ : Measure X
F : Set X
hF : IsClosed F
r : ℝ≥0∞
B : ℕ → Set X := compactCovering X
hr : r < ⨆ n, μ (F ∩ B n)
hBc : ∀ (n : ℕ), IsCompact (F ∩ B n)
hBU : ⋃ n, F ∩ B n = F
this : μ F = ⨆ n, μ (F ∩ B n)
n : ℕ
hn : r < μ (F ∩ B n)
⊢ ∃ K ⊆ F, IsCompact K ∧ r < μ K
state_after: no goals
tactic: exact ⟨_, inter_subset_left, hBc n, hn⟩