Proof using.
induction n; intros; simpl in *; auto.
- intuition.
assert (n' = 0) by omega. subst.
eauto using clients_move_up_in_queue.
- match goal with
| H : _ (hd s) |- _ =>
pattern s in H
end.
match goal with
| H1 : ?J1 s, H2 : ?J2 s, H3 : ?J3 s |- _ =>
assert ((J1 /\_ J2 /\_ J3) s) as Hand by (now unfold and_tl);
clear H1; clear H2; clear H3
end; simpl in *.
find_apply_lem_hyp le_lt_eq_dec. intuition.
+ assert (n' <= n) by omega.
find_eapply_lem_hyp clients_move_up_in_queue; eauto;
try solve [unfold and_tl in *; intuition]; [idtac].
eapply eventually_trans. 4:eauto.
3:apply Hand. all:unfold and_tl in *.
all:intuition eauto using lb_step_execution_invar, weak_fairness_invar.
find_apply_lem_hyp step_async_star_lb_step_execution; auto.
destruct s0. simpl in *.
find_apply_lem_hyp always_Cons.
intuition.
find_apply_lem_hyp always_Cons.
intuition.
+ subst. unfold and_tl in *. intuition.
eauto using clients_move_up_in_queue.
Qed.

Lemma clients_get_lock_messages :
forall n c s,
event_step_star step_async step_async_init (hd s) ->
lb_step_execution lb_step_async s ->
weak_fairness lb_step_async label_silent s ->
Nth (queue (nwState (evt_a (hd s)) Server)) (S n) c ->
eventually (fun s =>
In (mkPacket Server (Client c) Locked)
(nwPackets (evt_a (hd s)))) s.