l3lab/ntp-mathlib huggingface dataset:
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    

Proof state:
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
⊢ Tendsto (fun r => ↑↑μ (toMeasurable μ s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)

Next tactic:
apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · 

Proof state:
case hgf
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
⊢ ∀ᶠ (b : ℝ) in 𝓝[>] 0,
    ↑↑μ (s ∩ closedBall x b) / ↑↑μ (closedBall x b) ≤ ↑↑μ (toMeasurable μ s ∩ closedBall x b) / ↑↑μ (closedBall x b)

Next tactic:
refine' eventually_of_forall fun r => mul_le_mul_right' _ _
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      

Proof state:
case hgf
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
r : ℝ
⊢ ↑↑μ (s ∩ closedBall x r) ≤ ↑↑μ (toMeasurable μ s ∩ closedBall x r)

Next tactic:
exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · 

Proof state:
case hfh
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
⊢ ∀ᶠ (b : ℝ) in 𝓝[>] 0, ↑↑μ (toMeasurable μ s ∩ closedBall x b) / ↑↑μ (closedBall x b) ≤ 1

Next tactic:
filter_upwards [self_mem_nhdsWithin]
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      

Proof state:
case h
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
⊢ ∀ a ∈ Ioi 0, ↑↑μ (toMeasurable μ s ∩ closedBall x a) / ↑↑μ (closedBall x a) ≤ 1

Next tactic:
rintro r -
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      

Proof state:
case h
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
r : ℝ
⊢ ↑↑μ (toMeasurable μ s ∩ closedBall x r) / ↑↑μ (closedBall x r) ≤ 1

Next tactic:
apply ENNReal.div_le_of_le_mul
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      

Proof state:
case h.h
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
r : ℝ
⊢ ↑↑μ (toMeasurable μ s ∩ closedBall x r) ≤ 1 * ↑↑μ (closedBall x r)

Next tactic:
rw [one_mul]
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      rw [one_mul]
      

Proof state:
case h.h
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
r : ℝ
⊢ ↑↑μ (toMeasurable μ s ∩ closedBall x r) ≤ ↑↑μ (closedBall x r)

Next tactic:
exact measure_mono (inter_subset_right _ _)
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      rw [one_mul]
      exact measure_mono (inter_subset_right _ _)
  

Proof state:
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
this : Tendsto (fun r => ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1)
⊢ Tendsto (fun r => ↑↑μ (s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1)

Next tactic:
refine this.congr fun r => ?_
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      rw [one_mul]
      exact measure_mono (inter_subset_right _ _)
  refine this.congr fun r => ?_
  

Proof state:
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
this : Tendsto (fun r => ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1)
r : ℝ
⊢ ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t) = ↑↑μ (s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)

Next tactic:
congr 1
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      rw [one_mul]
      exact measure_mono (inter_subset_right _ _)
  refine this.congr fun r => ?_
  congr 1
  

Proof state:
case e_a
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
this : Tendsto (fun r => ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1)
r : ℝ
⊢ ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) = ↑↑μ (s ∩ ({x} + r • t))

Next tactic:
apply measure_toMeasurable_inter_of_sFinite
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      rw [one_mul]
      exact measure_mono (inter_subset_right _ _)
  refine this.congr fun r => ?_
  congr 1
  apply measure_toMeasurable_inter_of_sFinite
  

Proof state:
case e_a.hs
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
this : Tendsto (fun r => ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1)
r : ℝ
⊢ MeasurableSet ({x} + r • t)

Next tactic:
simp only [image_add_left, singleton_add]
/-- Consider a point `x` at which a set `s` has density one, with respect to closed balls (i.e.,
a Lebesgue density point of `s`). Then `s` has also density one at `x` with respect to any
measurable set `t`: the proportion of points in `s` belonging to a rescaled copy `{x} + r • t`
of `t` tends to one as `r` tends to zero. -/
theorem tendsto_addHaar_inter_smul_one_of_density_one (s : Set E) (x : E)
    (h : Tendsto (fun r => μ (s ∩ closedBall x r) / μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)) (t : Set E)
    (ht : MeasurableSet t) (h't : μ t ≠ 0) (h''t : μ t ≠ ∞) :
    Tendsto (fun r : ℝ => μ (s ∩ ({x} + r • t)) / μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1) := by
  have : Tendsto (fun r : ℝ => μ (toMeasurable μ s ∩ ({x} + r • t)) / μ ({x} + r • t))
    (𝓝[>] 0) (𝓝 1) := by
    apply
      tendsto_addHaar_inter_smul_one_of_density_one_aux μ _ (measurableSet_toMeasurable _ _) _ _
        t ht h't h''t
    apply tendsto_of_tendsto_of_tendsto_of_le_of_le' h tendsto_const_nhds
    · refine' eventually_of_forall fun r => mul_le_mul_right' _ _
      exact measure_mono (inter_subset_inter_left _ (subset_toMeasurable _ _))
    · filter_upwards [self_mem_nhdsWithin]
      rintro r -
      apply ENNReal.div_le_of_le_mul
      rw [one_mul]
      exact measure_mono (inter_subset_right _ _)
  refine this.congr fun r => ?_
  congr 1
  apply measure_toMeasurable_inter_of_sFinite
  simp only [image_add_left, singleton_add]
  

Proof state:
case e_a.hs
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
inst✝⁴ : FiniteDimensional ℝ E
μ : Measure E
inst✝³ : IsAddHaarMeasure μ
F : Type u_2
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
s✝ s : Set E
x : E
h : Tendsto (fun r => ↑↑μ (s ∩ closedBall x r) / ↑↑μ (closedBall x r)) (𝓝[>] 0) (𝓝 1)
t : Set E
ht : MeasurableSet t
h't : ↑↑μ t ≠ 0
h''t : ↑↑μ t ≠ ⊤
this : Tendsto (fun r => ↑↑μ (toMeasurable μ s ∩ ({x} + r • t)) / ↑↑μ ({x} + r • t)) (𝓝[>] 0) (𝓝 1)
r : ℝ
⊢ MeasurableSet ((fun x_1 => -x + x_1) ⁻¹' (r • t))

Next tactic:
apply (continuous_add_left (-x)).measurable (ht.const_smul₀ r)