Goal:
  
  A : Type
  P : A → A → Type
  Q : A → Type
  l : list A
  l' : list A
  HPQ : ∀ x y : A, Q x → P x y → Q y
  ============================
   (OnOne2 P l l' → All Q l → All Q l')


DEBUG:Going to execute:
induction 1; intros H; depelim H