Section DEL_EFFECT.
(* invariants *)
Variable c0 : Config.
Variable s0 : Site.
Hypothesis rt_true : rt c0 s0 = true.

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).