l3lab/ntp-mathlib huggingface dataset:
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  

Proof state:
case intro.intro.intro.intro
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
⊢ μ = ν

Next tactic:
refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · 

Proof state:
case intro.intro.intro.intro.refine'_1
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
⊢ {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2} ⊆ {S | ∃ l u, l < u ∧ Ico l u = S}

Next tactic:
rintro _ ⟨l, -, u, -, h, rfl⟩
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    

Proof state:
case intro.intro.intro.intro.refine'_1.intro.intro.intro.intro.intro
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u✝ : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h✝ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
l u : α
h : l < u
⊢ Ico l u ∈ {S | ∃ l u, l < u ∧ Ico l u = S}

Next tactic:
exact ⟨l, u, h, rfl⟩
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · 

Proof state:
case intro.intro.intro.intro.refine'_2
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
⊢ ⋃₀ {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2} = univ

Next tactic:
refine' sUnion_eq_univ_iff.2 fun x => _
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · refine' sUnion_eq_univ_iff.2 fun x => _
    

Proof state:
case intro.intro.intro.intro.refine'_2
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x✝ : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
x : α
⊢ ∃ b ∈ {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}, x ∈ b

Next tactic:
rcases hsd.exists_le' hsb x with ⟨l, hls, hlx⟩
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · refine' sUnion_eq_univ_iff.2 fun x => _
    rcases hsd.exists_le' hsb x with ⟨l, hls, hlx⟩
    

Proof state:
case intro.intro.intro.intro.refine'_2.intro.intro
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x✝ : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
x l : α
hls : l ∈ s
hlx : l ≤ x
⊢ ∃ b ∈ {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}, x ∈ b

Next tactic:
rcases hsd.exists_gt x with ⟨u, hus, hxu⟩
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · refine' sUnion_eq_univ_iff.2 fun x => _
    rcases hsd.exists_le' hsb x with ⟨l, hls, hlx⟩
    rcases hsd.exists_gt x with ⟨u, hus, hxu⟩
    

Proof state:
case intro.intro.intro.intro.refine'_2.intro.intro.intro.intro
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u✝ : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x✝ : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
x l : α
hls : l ∈ s
hlx : l ≤ x
u : α
hus : u ∈ s
hxu : x < u
⊢ ∃ b ∈ {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}, x ∈ b

Next tactic:
exact ⟨_, ⟨l, hls, u, hus, hlx.trans_lt hxu, rfl⟩, hlx, hxu⟩
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · refine' sUnion_eq_univ_iff.2 fun x => _
    rcases hsd.exists_le' hsb x with ⟨l, hls, hlx⟩
    rcases hsd.exists_gt x with ⟨u, hus, hxu⟩
    exact ⟨_, ⟨l, hls, u, hus, hlx.trans_lt hxu, rfl⟩, hlx, hxu⟩
  · 

Proof state:
case intro.intro.intro.intro.refine'_3
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
⊢ ∀ s_1 ∈ {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}, ↑↑μ s_1 ≠ ⊤

Next tactic:
rintro _ ⟨l, -, u, -, hlt, rfl⟩
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · refine' sUnion_eq_univ_iff.2 fun x => _
    rcases hsd.exists_le' hsb x with ⟨l, hls, hlx⟩
    rcases hsd.exists_gt x with ⟨u, hus, hxu⟩
    exact ⟨_, ⟨l, hls, u, hus, hlx.trans_lt hxu, rfl⟩, hlx, hxu⟩
  · rintro _ ⟨l, -, u, -, hlt, rfl⟩
    

Proof state:
case intro.intro.intro.intro.refine'_3.intro.intro.intro.intro.intro
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u✝ : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
l u : α
hlt : l < u
⊢ ↑↑μ (Ico l u) ≠ ⊤

Next tactic:
exact hμ hlt
/-- Two measures which are finite on closed-open intervals are equal if they agree on all
closed-open intervals. -/
theorem ext_of_Ico' {α : Type*} [TopologicalSpace α] {m : MeasurableSpace α}
    [SecondCountableTopology α] [LinearOrder α] [OrderTopology α] [BorelSpace α] [NoMaxOrder α]
    (μ ν : Measure α) (hμ : ∀ ⦃a b⦄, a < b → μ (Ico a b) ≠ ∞)
    (h : ∀ ⦃a b⦄, a < b → μ (Ico a b) = ν (Ico a b)) : μ = ν := by
  rcases exists_countable_dense_bot_top α with ⟨s, hsc, hsd, hsb, _⟩
  have : (⋃ (l ∈ s) (u ∈ s) (_ : l < u), {Ico l u} : Set (Set α)).Countable :=
    hsc.biUnion fun l _ => hsc.biUnion fun u _ => countable_iUnion fun _ => countable_singleton _
  simp only [← setOf_eq_eq_singleton, ← setOf_exists] at this
  refine'
    Measure.ext_of_generateFrom_of_cover_subset
      (BorelSpace.measurable_eq.trans (borel_eq_generateFrom_Ico α)) (isPiSystem_Ico id id) _ this
      _ _ _
  · rintro _ ⟨l, -, u, -, h, rfl⟩
    exact ⟨l, u, h, rfl⟩
  · refine' sUnion_eq_univ_iff.2 fun x => _
    rcases hsd.exists_le' hsb x with ⟨l, hls, hlx⟩
    rcases hsd.exists_gt x with ⟨u, hus, hxu⟩
    exact ⟨_, ⟨l, hls, u, hus, hlx.trans_lt hxu, rfl⟩, hlx, hxu⟩
  · rintro _ ⟨l, -, u, -, hlt, rfl⟩
    exact hμ hlt
  · 

Proof state:
case intro.intro.intro.intro.refine'_4
α✝ : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι : Sort y
s✝ t u : Set α✝
inst✝²² : TopologicalSpace α✝
inst✝²¹ : MeasurableSpace α✝
inst✝²⁰ : OpensMeasurableSpace α✝
inst✝¹⁹ : TopologicalSpace β
inst✝¹⁸ : MeasurableSpace β
inst✝¹⁷ : OpensMeasurableSpace β
inst✝¹⁶ : TopologicalSpace γ
inst✝¹⁵ : MeasurableSpace γ
inst✝¹⁴ : BorelSpace γ
inst✝¹³ : TopologicalSpace γ₂
inst✝¹² : MeasurableSpace γ₂
inst✝¹¹ : BorelSpace γ₂
inst✝¹⁰ : MeasurableSpace δ
α' : Type u_6
inst✝⁹ : TopologicalSpace α'
inst✝⁸ : MeasurableSpace α'
inst✝⁷ : LinearOrder α✝
inst✝⁶ : OrderClosedTopology α✝
a b x : α✝
α : Type u_7
inst✝⁵ : TopologicalSpace α
m : MeasurableSpace α
inst✝⁴ : SecondCountableTopology α
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : BorelSpace α
inst✝ : NoMaxOrder α
μ ν : Measure α
hμ : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) ≠ ⊤
h : ∀ ⦃a b : α⦄, a < b → ↑↑μ (Ico a b) = ↑↑ν (Ico a b)
s : Set α
hsc : Set.Countable s
hsd : Dense s
hsb : ∀ (x : α), IsBot x → x ∈ s
right✝ : ∀ (x : α), IsTop x → x ∈ s
this : Set.Countable {x | ∃ i, ∃ (_ : i ∈ s), ∃ i_2, ∃ (_ : i_2 ∈ s) (_ : i < i_2), x = Ico i i_2}
⊢ ∀ s ∈ {S | ∃ l u, l < u ∧ Ico l u = S}, ↑↑μ s = ↑↑ν s

Next tactic:
rintro _ ⟨l, u, hlt, rfl⟩