intros m; induction m; intros;
destruct v; simpl; auto.
Qed.

(* Specifications: *)
Lemma unset_other : forall m v v',
v <> v' ->
get (unset m v) v' = get m v'.
Lemma unset_other : forall m v v',
v <> v' ->
get (unset m v) v' = get m v'.
Lemma unset_other : forall m v v',
v <> v' ->
get (unset m v) v' = get m v'.