(* démo si mapget power predta_coacc = true alors l'état est coaccessible *)

Lemma predta_coacc_0_rev :
forall (d d' : preDTA) (b : ad) (m : Map bool),
MapGet bool (predta_coacc_0 d d' m) b = Some true ->
ensemble_base state d' m ->
exists a : ad,
(exists s : state,
(exists c : ad,
(exists p : prec_list,
MapGet state d' a = Some s /\
MapGet prec_list s c = Some p /\
prec_occur p b /\ MapGet bool m a = Some true))).