Proof using.
induction tr1; intros; simpl.
- auto.
- rewrite IHtr1.
repeat break_match; subst.
+ auto.
+ rewrite app_ass. auto.
Qed.

(* Specifications: *)
Lemma simulation :
forall net tr,
step_async_star step_async_init net tr ->
step_1_star init (revert_state net) (revert_trace tr).