加者 6人
Require Import Arith. Theorem not_eq_beq_false : forall n n' : nat, n <> n' -> beq_nat n n' = false. Proof. induction n; destruct n'; simpl; intros; try reflexivity. induction H; reflexivity. apply IHn. intro H'; rewrite H' in *; apply H. reflexivity. Qed.