Goal:
  
  A : Type
  B : Type
  P : B → A → A → Type
  Q : A → Type
  i : list B
  l : list A
  l' : list A
  HPQ : ∀ (i : B) (x y : A), Q x → P i x y → Q y
  ============================
   (OnOne2All P i l l' → All Q l → All Q l')


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