“…For instance, the flattable systems admit a flat finite unfolding of the control graph with the same reachability set. On the logical side, temporal logics with Presburger constraints have been defined and investigated in (Čerans, 1994;Bouajjani et al, 1995;Bultan et al, 1997;Comon et al, 2000;Schuele et al, 2004;Demri, 2006;Bruyère et al, 2003), some of which have quite expressive decidable fragments. However, undecidability of the reachability problem can be proved for quite restricted counter systems, see e.g.…”