(* This code is copyrighted by its authors; it is distributed under  *)
(* the terms of the LGPL license (see LICENSE and description files) *)
Definition DecRel (A : Set) (R : Rel A) :=
forall x y : A, {R x y} + {~ R x y}.
(* A computational double induction rule *)

Lemma dec_lt : DecRel nat lt.
red in |- *; intros; pattern x, y in |- *.