The power of mobility: Four membranes suffice

Abstract

We continue the study of P systems with mobile membranes introduced in [6], which is a variant of P systems with active membranes having none of the features like polarizations, label change and division of non-elementary membranes. This variant was shown to be universal using only the simple operations of endocytosis and exocytosis; moreover, if elementary membrane division is allowed, it is capable of solving hard problems. Here, we investigate the power of the two operations (endocytosis, exocytosis) in more detail: 2 membranes can generate sets of vectors outside PsMAT, and four membranes give universality. © Springer-Verlag Berlin Heidelberg 2005.