l3lab/ntp-mathlib huggingface dataset:
/-- A set of points `s` satisfying both `ρ a ≤ c * μ a` and `ρ a ≥ d * μ a` at arbitrarily small
sets in a Vitali family has measure `0` if `c < d`. Indeed, the first inequality should imply
that `ρ s ≤ c * μ s`, and the second one that `ρ s ≥ d * μ s`, a contradiction if `0 < μ s`. -/
theorem null_of_frequently_le_of_frequently_ge {c d : ℝ≥0} (hcd : c < d) (s : Set α)
    (hc : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, ρ a ≤ c * μ a)
    (hd : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, (d : ℝ≥0∞) * μ a ≤ ρ a) : μ s = 0 := by
  apply null_of_locally_null s fun x _ => ?_
  obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ μ o < ∞ :=
    Measure.exists_isOpen_measure_lt_top μ x
  refine' ⟨s ∩ o, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), _⟩
  let s' := s ∩ o
  by_contra h
  

Proof state:
case intro.intro.intro
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
c d : ℝ≥0
hcd : c < d
s : Set α
hc : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a
hd : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑d * ↑↑μ a ≤ ↑↑ρ a
x : α
x✝ : x ∈ s
o : Set α
xo : x ∈ o
o_open : IsOpen o
μo : ↑↑μ o < ⊤
s' : Set α := s ∩ o
h : ¬↑↑μ (s ∩ o) = 0
⊢ False

Next tactic:
apply lt_irrefl (ρ s')
/-- A set of points `s` satisfying both `ρ a ≤ c * μ a` and `ρ a ≥ d * μ a` at arbitrarily small
sets in a Vitali family has measure `0` if `c < d`. Indeed, the first inequality should imply
that `ρ s ≤ c * μ s`, and the second one that `ρ s ≥ d * μ s`, a contradiction if `0 < μ s`. -/
theorem null_of_frequently_le_of_frequently_ge {c d : ℝ≥0} (hcd : c < d) (s : Set α)
    (hc : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, ρ a ≤ c * μ a)
    (hd : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, (d : ℝ≥0∞) * μ a ≤ ρ a) : μ s = 0 := by
  apply null_of_locally_null s fun x _ => ?_
  obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ μ o < ∞ :=
    Measure.exists_isOpen_measure_lt_top μ x
  refine' ⟨s ∩ o, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), _⟩
  let s' := s ∩ o
  by_contra h
  apply lt_irrefl (ρ s')
  

Proof state:
case intro.intro.intro
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
c d : ℝ≥0
hcd : c < d
s : Set α
hc : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a
hd : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑d * ↑↑μ a ≤ ↑↑ρ a
x : α
x✝ : x ∈ s
o : Set α
xo : x ∈ o
o_open : IsOpen o
μo : ↑↑μ o < ⊤
s' : Set α := s ∩ o
h : ¬↑↑μ (s ∩ o) = 0
⊢ ↑↑ρ s' < ↑↑ρ s'

Next tactic:
calc
    ρ s' ≤ c * μ s' := v.measure_le_of_frequently_le (c • μ) hρ s' fun x hx => hc x hx.1
    _ < d * μ s' := by
      apply (ENNReal.mul_lt_mul_right h _).2 (ENNReal.coe_lt_coe.2 hcd)
      exact (lt_of_le_of_lt (measure_mono (inter_subset_right _ _)) μo).ne
    _ ≤ ρ s' :=
      v.measure_le_of_frequently_le ρ ((Measure.AbsolutelyContinuous.refl μ).smul d) s' fun x hx =>
        hd x hx.1
/-- A set of points `s` satisfying both `ρ a ≤ c * μ a` and `ρ a ≥ d * μ a` at arbitrarily small
sets in a Vitali family has measure `0` if `c < d`. Indeed, the first inequality should imply
that `ρ s ≤ c * μ s`, and the second one that `ρ s ≥ d * μ s`, a contradiction if `0 < μ s`. -/
theorem null_of_frequently_le_of_frequently_ge {c d : ℝ≥0} (hcd : c < d) (s : Set α)
    (hc : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, ρ a ≤ c * μ a)
    (hd : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, (d : ℝ≥0∞) * μ a ≤ ρ a) : μ s = 0 := by
  apply null_of_locally_null s fun x _ => ?_
  obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ μ o < ∞ :=
    Measure.exists_isOpen_measure_lt_top μ x
  refine' ⟨s ∩ o, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), _⟩
  let s' := s ∩ o
  by_contra h
  apply lt_irrefl (ρ s')
  calc
    ρ s' ≤ c * μ s' := v.measure_le_of_frequently_le (c • μ) hρ s' fun x hx => hc x hx.1
    _ < d * μ s' := by
      

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
c d : ℝ≥0
hcd : c < d
s : Set α
hc : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a
hd : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑d * ↑↑μ a ≤ ↑↑ρ a
x : α
x✝ : x ∈ s
o : Set α
xo : x ∈ o
o_open : IsOpen o
μo : ↑↑μ o < ⊤
s' : Set α := s ∩ o
h : ¬↑↑μ (s ∩ o) = 0
⊢ ↑c * ↑↑μ s' < ↑d * ↑↑μ s'

Next tactic:
apply (ENNReal.mul_lt_mul_right h _).2 (ENNReal.coe_lt_coe.2 hcd)
/-- A set of points `s` satisfying both `ρ a ≤ c * μ a` and `ρ a ≥ d * μ a` at arbitrarily small
sets in a Vitali family has measure `0` if `c < d`. Indeed, the first inequality should imply
that `ρ s ≤ c * μ s`, and the second one that `ρ s ≥ d * μ s`, a contradiction if `0 < μ s`. -/
theorem null_of_frequently_le_of_frequently_ge {c d : ℝ≥0} (hcd : c < d) (s : Set α)
    (hc : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, ρ a ≤ c * μ a)
    (hd : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, (d : ℝ≥0∞) * μ a ≤ ρ a) : μ s = 0 := by
  apply null_of_locally_null s fun x _ => ?_
  obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ μ o < ∞ :=
    Measure.exists_isOpen_measure_lt_top μ x
  refine' ⟨s ∩ o, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), _⟩
  let s' := s ∩ o
  by_contra h
  apply lt_irrefl (ρ s')
  calc
    ρ s' ≤ c * μ s' := v.measure_le_of_frequently_le (c • μ) hρ s' fun x hx => hc x hx.1
    _ < d * μ s' := by
      apply (ENNReal.mul_lt_mul_right h _).2 (ENNReal.coe_lt_coe.2 hcd)
      

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
c d : ℝ≥0
hcd : c < d
s : Set α
hc : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a
hd : ∀ x ∈ s, ∃ᶠ (a : Set α) in filterAt v x, ↑d * ↑↑μ a ≤ ↑↑ρ a
x : α
x✝ : x ∈ s
o : Set α
xo : x ∈ o
o_open : IsOpen o
μo : ↑↑μ o < ⊤
s' : Set α := s ∩ o
h : ¬↑↑μ (s ∩ o) = 0
⊢ ↑↑μ (s ∩ o) ≠ ⊤

Next tactic:
exact (lt_of_le_of_lt (measure_mono (inter_subset_right _ _)) μo).ne
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
⊢ ∀ᵐ (x : α) ∂μ, ∃ c, Tendsto (fun a => ↑↑ρ a / ↑↑μ a) (filterAt v x) (𝓝 c)

Next tactic:
obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  

Proof state:
case intro.intro.intro.intro
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
⊢ ∀ᵐ (x : α) ∂μ, ∃ c, Tendsto (fun a => ↑↑ρ a / ↑↑μ a) (filterAt v x) (𝓝 c)

Next tactic:
have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  

Proof state:
case intro.intro.intro.intro
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
⊢ ∀ᵐ (x : α) ∂μ, ∃ c, Tendsto (fun a => ↑↑ρ a / ↑↑μ a) (filterAt v x) (𝓝 c)

Next tactic:
have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
    · simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
      intro x h1x _
      apply h1x.mono fun a ha => ?_
      refine' (ENNReal.div_le_iff_le_mul _ (Or.inr (bot_le.trans_lt ha).ne')).1 ha.le
      simp only [ENNReal.coe_ne_top, Ne.def, or_true_iff, not_false_iff]
    · simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
      intro x _ h2x
      apply h2x.mono fun a ha => ?_
      exact ENNReal.mul_le_of_le_div ha.le
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
⊢ ∀ c ∈ w,
    ∀ d ∈ w,
      c < d →
        ∀ᵐ (x : α) ∂μ,
          ¬((∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < c) ∧ ∃ᶠ (a : Set α) in filterAt v x, d < ↑↑ρ a / ↑↑μ a)

Next tactic:
intro c hc d hd hcd
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0∞
hc : c ∈ w
d : ℝ≥0∞
hd : d ∈ w
hcd : c < d
⊢ ∀ᵐ (x : α) ∂μ,
    ¬((∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < c) ∧ ∃ᶠ (a : Set α) in filterAt v x, d < ↑↑ρ a / ↑↑μ a)

Next tactic:
lift c to ℝ≥0 using I c hc
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    

Proof state:
case intro
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
d : ℝ≥0∞
hd : d ∈ w
c : ℝ≥0
hc : ↑c ∈ w
hcd : ↑c < d
⊢ ∀ᵐ (x : α) ∂μ,
    ¬((∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c) ∧ ∃ᶠ (a : Set α) in filterAt v x, d < ↑↑ρ a / ↑↑μ a)

Next tactic:
lift d to ℝ≥0 using I d hd
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    

Proof state:
case intro.intro
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0
hc : ↑c ∈ w
d : ℝ≥0
hd : ↑d ∈ w
hcd : ↑c < ↑d
⊢ ∀ᵐ (x : α) ∂μ,
    ¬((∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c) ∧ ∃ᶠ (a : Set α) in filterAt v x, ↑d < ↑↑ρ a / ↑↑μ a)

Next tactic:
apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
    · 

Proof state:
case intro.intro.hc
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0
hc : ↑c ∈ w
d : ℝ≥0
hd : ↑d ∈ w
hcd : ↑c < ↑d
⊢ ∀
    x ∈
      {x |
          (fun x =>
              ¬((∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c) ∧
                  ∃ᶠ (a : Set α) in filterAt v x, ↑d < ↑↑ρ a / ↑↑μ a))
            x}ᶜ,
    ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a

Next tactic:
simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
    · simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
      

Proof state:
case intro.intro.hc
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0
hc : ↑c ∈ w
d : ℝ≥0
hd : ↑d ∈ w
hcd : ↑c < ↑d
⊢ ∀ (x : α),
    (∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c) →
      (∃ᶠ (x : Set α) in filterAt v x, ↑d < ↑↑ρ x / ↑↑μ x) → ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a

Next tactic:
intro x h1x _
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
    · simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
      intro x h1x _
      

Proof state:
case intro.intro.hc
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0
hc : ↑c ∈ w
d : ℝ≥0
hd : ↑d ∈ w
hcd : ↑c < ↑d
x : α
h1x : ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c
a✝ : ∃ᶠ (x : Set α) in filterAt v x, ↑d < ↑↑ρ x / ↑↑μ x
⊢ ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a ≤ ↑c * ↑↑μ a

Next tactic:
apply h1x.mono fun a ha => ?_
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
    · simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
      intro x h1x _
      apply h1x.mono fun a ha => ?_
      

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0
hc : ↑c ∈ w
d : ℝ≥0
hd : ↑d ∈ w
hcd : ↑c < ↑d
x : α
h1x : ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c
a✝ : ∃ᶠ (x : Set α) in filterAt v x, ↑d < ↑↑ρ x / ↑↑μ x
a : Set α
ha : ↑↑ρ a / ↑↑μ a < ↑c
⊢ ↑↑ρ a ≤ ↑c * ↑↑μ a

Next tactic:
refine' (ENNReal.div_le_iff_le_mul _ (Or.inr (bot_le.trans_lt ha).ne')).1 ha.le
/-- If `ρ` is absolutely continuous with respect to `μ`, then for almost every `x`,
the ratio `ρ a / μ a` converges as `a` shrinks to `x` along a Vitali family for `μ`. -/
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
  obtain ⟨w, w_count, w_dense, _, w_top⟩ :
    ∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
    ENNReal.exists_countable_dense_no_zero_top
  have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
  have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
      ¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
    intro c hc d hd hcd
    lift c to ℝ≥0 using I c hc
    lift d to ℝ≥0 using I d hd
    apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
    · simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
        mem_setOf_eq, mem_compl_iff, not_forall]
      intro x h1x _
      apply h1x.mono fun a ha => ?_
      refine' (ENNReal.div_le_iff_le_mul _ (Or.inr (bot_le.trans_lt ha).ne')).1 ha.le
      

Proof state:
α : Type u_1
inst✝⁵ : MetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ≪ μ
w : Set ℝ≥0∞
w_count : Set.Countable w
w_dense : Dense w
left✝ : 0 ∉ w
w_top : ⊤ ∉ w
I : ∀ x ∈ w, x ≠ ⊤
c : ℝ≥0
hc : ↑c ∈ w
d : ℝ≥0
hd : ↑d ∈ w
hcd : ↑c < ↑d
x : α
h1x : ∃ᶠ (a : Set α) in filterAt v x, ↑↑ρ a / ↑↑μ a < ↑c
a✝ : ∃ᶠ (x : Set α) in filterAt v x, ↑d < ↑↑ρ x / ↑↑μ x
a : Set α
ha : ↑↑ρ a / ↑↑μ a < ↑c
⊢ ↑↑μ a ≠ 0 ∨ ↑c ≠ ⊤

Next tactic:
simp only [ENNReal.coe_ne_top, Ne.def, or_true_iff, not_false_iff]