theorem extracted_formal_statement_6.{w, v, u} {Z : Type w} {ι : Type v} {f : ι → Z → ℝ} {Ω : Type u}
  [inst : MeasurableSpace Ω] {X : Ω → Z} [inst_1 : Countable ι] (h𝓕 : ∀ (I : ι), Measurable (f I ∘ X)) {n : ℕ} {I : ι}
  {i : Fin n} : Measurable fun ω => f I (X (ω i).1) - f I (X (ω i).2) := sorry

State before:
Z : Type w
ι : Type v
f : ι → Z → ℝ
Ω : Type u
inst✝¹ : MeasurableSpace Ω
X : Ω → Z
inst✝ : Countable ι
h𝓕 : ∀ (I : ι), Measurable (f I ∘ X)
n : ℕ
I : ι
i : Fin n
⊢ Measurable fun ω => f I (X (ω i).1) - f I (X (ω i).2)

Tactic: apply Measurable.sub
    ·
  apply (h𝓕 I).comp
  apply measurable_fst.comp
  exact measurable_pi_apply i
    ·
  apply (h𝓕 I).comp
  apply measurable_snd.comp
  exact measurable_pi_apply i

State after:

Relevant lemmas:
measurable_pi_apply : ∀ {δ : Type u_4} {X : δ → Type u_6} [inst : (a : δ) → MeasurableSpace (X a)] (a : δ),
  Measurable fun f => f a
Measurable.sub : ∀ {G : Type u_2} {α : Type u_3} [inst : MeasurableSpace G] [inst_2 : Sub G] {m : MeasurableSpace α}
  {f g : α → G} [inst_3 : MeasurableSub₂ G], Measurable f → Measurable g → Measurable fun a => f a - g a