On Reversibility and Determinism in P Systems

Membrane computing is a formal framework of distributed parallel computing. In this paper we study the reversibility and maximal parallelism of P systems from the computability point of view. The notions of reversible and strongly reversible systems are considered. The universality is shown for one class and a negative conjecture is stated for a more restricted class of reversible P systems. For one class of strongly reversible P systems, a very strong limitation is shown, and it is shown that this limitation does not hold for a less restricted class. Another concept considered is strong determinism, which is a syntactic property, as opposed to the determinism typically considered in membrane computing. A limitation is shown of one class, while a less restricted class is universal.