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

Lemma del_trans_rt :
forall s1 : Site,
Int (rt (delete_trans c0 s0) s1) =
(if eq_site_dec s1 s0
then  (Int (rt c0 s1) - 1)%Z
else  Int (rt c0 s1)).