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


DEBUG:Going to execute:
induction 1; split; constructor