Definition sequence_sane (net : seq_num_network) :=
    (forall p,
       In p (nwPackets net) ->
       tmNum (pBody p) < (tdNum ((nwState net) (pSrc p)))).

(* Specifications: *)
Lemma reachable_sane : true_in_reachable step_dup step_async_init sequence_sane.
Lemma reachable_seen : true_in_reachable step_dup step_async_init sequence_seen.