intros js age a. simpl; unfold OrdinalPool.lockRes; destruct js.
simpl.
intros AA.
apply AMap_find_map_inv in AA. destruct AA as [x [map rest]].
rewrite map. f_equal.
destruct x; inversion rest; try reflexivity.
Qed.

Lemma LockRes_age_content2: forall js age a rm,
lockRes (age_tp_to age js) a = Some (Some rm) ->
exists r, lockRes js a = Some (Some r) /\ rm = age_to age r.