Goal:
  
  ============================
   (∀ (A B : Type) (R : nat → A → B → Type) (n : nat) 
      (l0 : list A) (l : list B) (a b : All2i R n l0 l),
      a = b → NoConfusionHom_All2i A B R n l0 l a b)


DEBUG:Going to execute:
simpl; intros