Proof using.
unfold zero_or_one_outputs_per_step_trace, zero_or_one_outputs_per_step.
simpl. intuition. subst. discriminate.
Qed.

(* Specifications: *)
Theorem pbj_0_or_1 :
forall net tr,
step_async_star (params:=PB_multi_params) step_async_init net tr ->
zero_or_one_outputs_per_step_trace tr.