Goal:
  
  A : Type
  P : list A → A → Type
  Q : list A → list A → A → A → Type
  Γ : list A
  Γ' : list A
  ============================
   (All_fold P Γ
    → All2_fold Q Γ Γ'
      → All2_fold (λ (Γ Γ' : list A) (d d' : A), P Γ d × Q Γ Γ' d d') Γ Γ')


DEBUG:Going to execute:
induction 1 in Γ' |- *; intros H; depelim H; constructor