Axiom
sigma_rooted_change_queue :
forall (s0 s1 s2 : Site) (b : Bag_of_message) (q : queue Message),
s0 <> owner ->
b s1 owner = input Message dec (input Message (inc_dec s2) q) ->
sigma_rooted s0 (change_queue (queue Message) b s1 owner q) =
(sigma_rooted s0 b - rooted_fun s0 s1 owner dec -
rooted_fun s0 s1 owner (inc_dec s2))%Z.
End ROOTED1.
Section INVARIANT2.

Lemma invariant2_ind :
forall s0 : Site,
s0 <> owner ->
forall (c : Config) (t : class_trans c),
legal c ->
st c s0 = sigma_rooted s0 (bm c) ->
st (transition c t) s0 = sigma_rooted s0 (bm (transition c t)).