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_in_queue : forall s1 s3 s4 : Site, In_queue Message (inc_dec s0) (bm (delete_trans c0 s1) s3 s4) -> In_queue Message (inc_dec s0) (bm c0 s3 s4).