Module: Mathlib.MeasureTheory.Integral.SetToL1

Goal state before:
pp: case pos.refine_1
α : Type u_1
E : Type u_2
F : Type u_3
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace ℝ E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
m : MeasurableSpace α
μ : Measure α
T : Set α → E →L[ℝ] F
C : ℝ
β : Type u_7
mβ : MeasurableSpace β
inst✝ : SFinite μ
hT : DominatedFinMeasAdditive μ T C
h'T : ∀ (s : Set (β × α)), MeasurableSet s → StronglyMeasurable fun x ↦ T (Prod.mk x ⁻¹' s)
f : β → α → E
hf : StronglyMeasurable (Function.uncurry f)
hF : CompleteSpace F
this✝² : MeasurableSpace E := borel E
this✝¹ : BorelSpace E
this✝ : SeparableSpace ↑(range (Function.uncurry f) ∪ {0})
s : ℕ → SimpleFunc (β × α) E := SimpleFunc.approxOn (Function.uncurry f) ⋯ (range (Function.uncurry f) ∪ {0}) 0 ⋯
s' : ℕ → β → SimpleFunc α E := fun n x ↦ (s n).comp (Prod.mk x) ⋯
f' : ℕ → β → F := fun n ↦ {x | Integrable (f x) μ}.indicator fun x ↦ SimpleFunc.setToSimpleFunc T (s' n x)
hf' : ∀ (n : ℕ), StronglyMeasurable (f' n)
x : β
hfx : Integrable (f x) μ
this : ∀ (n : ℕ), Integrable (⇑(s' n x)) μ
⊢ ∀ (n : ℕ), ∀ᵐ (a : α) ∂μ, ‖(s' n x) a‖ ≤ ‖f x a‖ + ‖f x a‖

pp: case pos.refine_2
α : Type u_1
E : Type u_2
F : Type u_3
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace ℝ E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
m : MeasurableSpace α
μ : Measure α
T : Set α → E →L[ℝ] F
C : ℝ
β : Type u_7
mβ : MeasurableSpace β
inst✝ : SFinite μ
hT : DominatedFinMeasAdditive μ T C
h'T : ∀ (s : Set (β × α)), MeasurableSet s → StronglyMeasurable fun x ↦ T (Prod.mk x ⁻¹' s)
f : β → α → E
hf : StronglyMeasurable (Function.uncurry f)
hF : CompleteSpace F
this✝² : MeasurableSpace E := borel E
this✝¹ : BorelSpace E
this✝ : SeparableSpace ↑(range (Function.uncurry f) ∪ {0})
s : ℕ → SimpleFunc (β × α) E := SimpleFunc.approxOn (Function.uncurry f) ⋯ (range (Function.uncurry f) ∪ {0}) 0 ⋯
s' : ℕ → β → SimpleFunc α E := fun n x ↦ (s n).comp (Prod.mk x) ⋯
f' : ℕ → β → F := fun n ↦ {x | Integrable (f x) μ}.indicator fun x ↦ SimpleFunc.setToSimpleFunc T (s' n x)
hf' : ∀ (n : ℕ), StronglyMeasurable (f' n)
x : β
hfx : Integrable (f x) μ
this : ∀ (n : ℕ), Integrable (⇑(s' n x)) μ
⊢ ∀ᵐ (a : α) ∂μ, Tendsto (fun n ↦ (s' n x) a) atTop (𝓝 (f x a))

Tactic:
· refine fun n => Eventually.of_forall fun y =>
          SimpleFunc.norm_approxOn_zero_le ?_ ?_ (x, y) n
        · exact hf.measurable
        · simp

Goal state after:
case pos.refine_2
α : Type u_1
E : Type u_2
F : Type u_3
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace ℝ E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
m : MeasurableSpace α
μ : Measure α
T : Set α → E →L[ℝ] F
C : ℝ
β : Type u_7
mβ : MeasurableSpace β
inst✝ : SFinite μ
hT : DominatedFinMeasAdditive μ T C
h'T : ∀ (s : Set (β × α)), MeasurableSet s → StronglyMeasurable fun x ↦ T (Prod.mk x ⁻¹' s)
f : β → α → E
hf : StronglyMeasurable (Function.uncurry f)
hF : CompleteSpace F
this✝² : MeasurableSpace E := borel E
this✝¹ : BorelSpace E
this✝ : SeparableSpace ↑(range (Function.uncurry f) ∪ {0})
s : ℕ → SimpleFunc (β × α) E := SimpleFunc.approxOn (Function.uncurry f) ⋯ (range (Function.uncurry f) ∪ {0}) 0 ⋯
s' : ℕ → β → SimpleFunc α E := fun n x ↦ (s n).comp (Prod.mk x) ⋯
f' : ℕ → β → F := fun n ↦ {x | Integrable (f x) μ}.indicator fun x ↦ SimpleFunc.setToSimpleFunc T (s' n x)
hf' : ∀ (n : ℕ), StronglyMeasurable (f' n)
x : β
hfx : Integrable (f x) μ
this : ∀ (n : ℕ), Integrable (⇑(s' n x)) μ
⊢ ∀ᵐ (a : α) ∂μ, Tendsto (fun n ↦ (s' n x) a) atTop (𝓝 (f x a))