-- Mathlib/Analysis/SpecialFunctions/JapaneseBracket.lean
theorem finite_integral_one_add_norm {r : ℝ} (hnr : (finrank ℝ E : ℝ) < r) :
    (∫⁻ x : E, ENNReal.ofReal ((1 + ‖x‖) ^ (-r)) ∂μ) < ∞

Proof state:
case calc_2
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
mB : ℝ≥0∞ := μ (Metric.ball 0 1)
h_int'' : ∀ t ∈ Ioi 1, f t = 0
⊢ 0 < ⊤

Tactic:
exact WithTop.top_pos

Result:
no goals

Proof state:
case calc_2
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
mB : ℝ≥0∞ := μ (Metric.ball 0 1)
⊢ ∫⁻ (t : ℝ) in Ioi 1, f t < ⊤

Tactic:
have h_int'' : ∀ t ∈ Ioi (1 : ℝ), f t = 0 := fun t ht => by
  simp only [f, closedBall_rpow_sub_one_eq_empty_aux E hr ht, measure_empty]

Result:
case calc_2
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
mB : ℝ≥0∞ := μ (Metric.ball 0 1)
h_int'' : ∀ t ∈ Ioi 1, f t = 0
⊢ ∫⁻ (t : ℝ) in Ioi 1, f t < ⊤

Proof state:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
⊢ ∫⁻ (t : ℝ) in Ioi 0, μ {a | t ≤ (1 + ‖a‖) ^ (-r)} < ⊤

Tactic:
have h_int : ∀ t, 0 < t → μ {a : E | t ≤ (1 + ‖a‖) ^ (-r)} =
    μ (Metric.closedBall (0 : E) (t ^ (-r⁻¹) - 1)) := fun t ht ↦ by
  congr 1
  ext x
  simp only [mem_setOf_eq, mem_closedBall_zero_iff]
  exact le_rpow_one_add_norm_iff_norm_le hr (mem_Ioi.mp ht) x

Result:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
⊢ ∫⁻ (t : ℝ) in Ioi 0, μ {a | t ≤ (1 + ‖a‖) ^ (-r)} < ⊤

Proof state:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
⊢ ∫⁻ (x : E), ENNReal.ofReal ((1 + ‖x‖) ^ (-r)) ∂μ < ⊤

Tactic:
have h_pos : ∀ x : E, 0 ≤ (1 + ‖x‖) ^ (-r) := fun x ↦ by positivity

Result:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
⊢ ∫⁻ (x : E), ENNReal.ofReal ((1 + ‖x‖) ^ (-r)) ∂μ < ⊤

Proof state:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
⊢ ∫⁻ (t : ℝ) in Ioi 0, μ {a | t ≤ (1 + ‖a‖) ^ (-r)} < ⊤

Tactic:
rw [setLIntegral_congr_fun measurableSet_Ioi (Eventually.of_forall h_int)]

Result:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
⊢ ∫⁻ (x : ℝ) in Ioi 0, μ (Metric.closedBall 0 (x ^ (-r⁻¹) - 1)) ∂volume < ⊤

Proof state:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
mB : ℝ≥0∞ := μ (Metric.ball 0 1)
t : ℝ
ht : t ∈ Ioi 1
⊢ f t = 0

Tactic:
simp only [f, closedBall_rpow_sub_one_eq_empty_aux E hr ht, measure_empty]

Result:
no goals

Proof state:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
⊢ lintegral (volume.restrict (Ioi 0)) f < ⊤

Tactic:
set mB := μ (Metric.ball (0 : E) 1)

Result:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
mB : ℝ≥0∞ := μ (Metric.ball 0 1)
⊢ lintegral (volume.restrict (Ioi 0)) f < ⊤

Proof state:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
r : ℝ
hnr : ↑(finrank ℝ E) < r
hr : 0 < r
h_meas : Measurable fun ω => (1 + ‖ω‖) ^ (-r)
h_pos : ∀ (x : E), 0 ≤ (1 + ‖x‖) ^ (-r)
h_int : ∀ (t : ℝ), 0 < t → μ {a | t ≤ (1 + ‖a‖) ^ (-r)} = μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
f : ℝ → ℝ≥0∞ := fun t => μ (Metric.closedBall 0 (t ^ (-r⁻¹) - 1))
mB : ℝ≥0∞ := μ (Metric.ball 0 1)
t : ℝ
ht : t ∈ Ioc 0 1
⊢ -r⁻¹ ≤ 0

Tactic:
simp [hr.le]

Result:
no goals