Section INVARIANT5.
(* In this file, we establish the following inequality Int + Sum copy + Sum dec - Sum inc_dec >= 0  *)
(* The message queue between a site and the owner has a particular structure.  Messages dec and inc_dec are alternated. *)

Lemma invariant5 :
forall c : Config,
legal c ->
forall s : Site,
(Int (rt c s) + reduce Message dec_count (bm c s owner) +
reduce Message copy_count (bm c owner s) -
reduce Message new_inc_count (bm c s owner) >= 0)%Z.