Definition ltb (a b : ascii) : bool :=
  if compare a b is Lt then true else false.Definition leb (a b : ascii) : bool :=
  if compare a b is Gt then false else true.

(* Specifications: *)
Lemma leb_antisym (a b : ascii) : leb a b = true -> leb b a = true -> a = b.
Lemma leb_total (a b : ascii) : leb a b = true \/ leb b a = true.