Definition skip_action_wrapper :=
  Action skip_safe_coh skip_step_total skip_step_sem.

(* Specifications: *)
Lemma tryrecv_act_safe_coh s : tryrecv_act_safe s -> Coh W s.
Lemma tryrecv_act_step_total s: tryrecv_act_safe s -> exists s' r , tryrecv_act_step s s' r.
Lemma tryrecv_act_step_safe s1 s2 r: tryrecv_act_step s1 s2 r -> tryrecv_act_safe s1.
Lemma tryrecv_act_step_sem s1 (S : tryrecv_act_safe s1) s2 r: tryrecv_act_step s1 s2 r -> network_step W this s1 s2.