Definition delete_trans (c : Config) (s : Site) :=
  mkconfig (S (time c)) (dt c) (st c) (Reset_rec_table (rt c) s)
    (Post_message dec (bm c) s owner).

Lemma del_trans_le_dt_time : forall s1 : Site, dt c0 s1 <= time c0 -> dt (delete_trans c0 s0) s1 <= time (delete_trans c0 s0).