We introduce the notion of stateless multihead two-way (respectively, oneway) NFAs and stateless multicounter systems and relate them to P systems and vector addition systems. In particular, we investigate the decidability of the emptiness and reachability problems for these stateless automata and show that the results are applicable to similar questions concerning certain variants of P systems, namely, token systems and sequential tissue-like P systems.
Linmin Yang, Zhe Dang, Oscar H. Ibarra