Module: Mathlib.MeasureTheory.Function.ConvergenceInDistribution

Goal state before:
pp: case inr.inr
ι : Type u_1
E : Type u_2
Ω' : Type u_3
Ω'' : Type u_4
m' : MeasurableSpace Ω'
μ' : Measure Ω'
inst✝⁵ : IsProbabilityMeasure μ'
m'' : MeasurableSpace Ω''
μ'' : Measure Ω''
inst✝⁴ : IsProbabilityMeasure μ''
mE : MeasurableSpace E
l : Filter ι
inst✝³ : SeminormedAddCommGroup E
inst✝² : SecondCountableTopology E
inst✝¹ : BorelSpace E
X : ι → Ω'' → E
inst✝ : l.IsCountablyGenerated
Y : ι → Ω'' → E
Z : Ω' → E
hXZ : TendstoInDistribution X l Z (fun x ↦ μ'') μ'
hXY : TendstoInMeasure μ'' (Y - X) l 0
hY : ∀ (i : ι), AEMeasurable (Y i) μ''
hZ : AEMeasurable Z μ'
hX : ∀ (i : ι), AEMeasurable (X i) μ''
hE : Nonempty E
x₀ : E := hE.some
F : E → ℝ
M : ℝ
hF_bounded : ∀ (x y : E), dist (F x) (F y) ≤ M
L : NNReal
hF_lip : LipschitzWith L F
hF_cont : Continuous[PseudoMetricSpace.toUniformSpace.toTopologicalSpace, _] F
hL : 0 < L
ε : ℝ
hε : ε > 0
h_le :
  ∀ (n : ι),
    |∫ (ω : E), F ω ∂Measure.map (Y n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'| ≤
      ↑L * (ε / 2) + M * μ''.real {ω | ε / 2 ≤ ‖Y n ω - X n ω‖} +
        |∫ (ω : E), F ω ∂Measure.map (X n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'|
⊢ ∀ᶠ (n : ι) in l, |∫ (ω : E), F ω ∂Measure.map (Y n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'| < ↑L * ε

Tactic:
have h_tendsto :
      Tendsto (fun n ↦ L * (ε / 2) + M * μ''.real {ω | ε / 2 ≤ ‖Y n ω - X n ω‖}
        + |∫ ω, F ω ∂(μ''.map (X n)) - ∫ ω, F ω ∂(μ'.map Z)|) l (𝓝 (L * ε / 2)) := by
    suffices Tendsto (fun n ↦ L * (ε / 2) + M * μ''.real {ω | ε / 2 ≤ ‖Y n ω - X n ω‖}
        + |∫ ω, F ω ∂(μ''.map (X n)) - ∫ ω, F ω ∂(μ'.map Z)|) l (𝓝 (L * ε / 2 + M * 0 + 0)) by
      simpa
    refine (Tendsto.add ?_ (Tendsto.const_mul _ ?_)).add ?_
    · rw [mul_div_assoc]
      exact tendsto_const_nhds
    · simp only [tendstoInMeasure_iff_measureReal_norm, Pi.zero_apply, sub_zero] at hXY
      exact hXY (ε / 2) (by positivity)
    · replace hXZ := hXZ.tendsto
      simp_rw [tendsto_iff_forall_lipschitz_integral_tendsto] at hXZ
      simpa [tendsto_iff_dist_tendsto_zero] using! hXZ F ⟨M, hF_bounded⟩ ⟨L, hF_lip⟩

Goal state after:
case inr.inr
ι : Type u_1
E : Type u_2
Ω' : Type u_3
Ω'' : Type u_4
m' : MeasurableSpace Ω'
μ' : Measure Ω'
inst✝⁵ : IsProbabilityMeasure μ'
m'' : MeasurableSpace Ω''
μ'' : Measure Ω''
inst✝⁴ : IsProbabilityMeasure μ''
mE : MeasurableSpace E
l : Filter ι
inst✝³ : SeminormedAddCommGroup E
inst✝² : SecondCountableTopology E
inst✝¹ : BorelSpace E
X : ι → Ω'' → E
inst✝ : l.IsCountablyGenerated
Y : ι → Ω'' → E
Z : Ω' → E
hXZ : TendstoInDistribution X l Z (fun x ↦ μ'') μ'
hXY : TendstoInMeasure μ'' (Y - X) l 0
hY : ∀ (i : ι), AEMeasurable (Y i) μ''
hZ : AEMeasurable Z μ'
hX : ∀ (i : ι), AEMeasurable (X i) μ''
hE : Nonempty E
x₀ : E := hE.some
F : E → ℝ
M : ℝ
hF_bounded : ∀ (x y : E), dist (F x) (F y) ≤ M
L : NNReal
hF_lip : LipschitzWith L F
hF_cont : Continuous[PseudoMetricSpace.toUniformSpace.toTopologicalSpace, _] F
hL : 0 < L
ε : ℝ
hε : ε > 0
h_le :
  ∀ (n : ι),
    |∫ (ω : E), F ω ∂Measure.map (Y n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'| ≤
      ↑L * (ε / 2) + M * μ''.real {ω | ε / 2 ≤ ‖Y n ω - X n ω‖} +
        |∫ (ω : E), F ω ∂Measure.map (X n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'|
h_tendsto :
  Tendsto
    (fun n ↦
      ↑L * (ε / 2) + M * μ''.real {ω | ε / 2 ≤ ‖Y n ω - X n ω‖} +
        |∫ (ω : E), F ω ∂Measure.map (X n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'|)
    l (𝓝 (↑L * ε / 2))
⊢ ∀ᶠ (n : ι) in l, |∫ (ω : E), F ω ∂Measure.map (Y n) μ'' - ∫ (ω : E), F ω ∂Measure.map Z μ'| < ↑L * ε