Section M_ACTION.
Variable Message : Set.
Let Bag_of_message := Bag_of_Data Message.
(* This is taken straight from Jean's file *)
Definition Post_message (m0 : Message) (b0 : Bag_of_message)
(s0 s1 : Site) :=
change_queue (queue Message) b0 s0 s1 (input Message m0 (b0 s0 s1)).
Definition Collect_message (b0 : Bag_of_message) (s0 s1 : Site) :=
change_queue (queue Message) b0 s0 s1 (first_out Message (b0 s0 s1)).

Lemma collect_here :
forall (b0 : Bag_of_message) (s0 s1 : Site),
Collect_message b0 s0 s1 s0 s1 = first_out Message (b0 s0 s1).