Goal:
  
  A : Type
  B : Type
  C : Type
  f : A → B → C
  a : A
  l : list A
  IHl : ∀ l' : list B, #|map2 f l l'| = Init.Nat.min #|l| #|l'|
  ============================
   (0 = 0)


DEBUG:Going to execute:
intros; Zify.zify_pre_hook; zify_elim_let; zify_op;
            Zify.zify_iter_specs; Zify.zify_to_euclidean_division_equations;
            Zify.zify_post_hook