Section REC_COP3_EFFECT.
(* invariants *)
Variable c0 : Config.
Variable s0 s1 s2 s3 s4 : Site.
Hypothesis rt_true : rt c0 s2 = false.

Lemma rcop3_trans_diff_site :
(In_queue Message copy (bm c0 s3 s4) -> s3 <> s4) ->
In_queue Message copy (bm (rec_copy3_trans c0 s1 s2) s3 s4) -> s3 <> s4.