On the Power of P Automata

摘要

We study the computational power of P automata, variants of symport/antiport P systems which characterize string languages by applying a mapping to the sequence of multisets entering the system during computations. We consider the case when the input mapping is defined in such a way that it maps a multiset to the set of strings consisting of all permutations of its elements. We show that the computational power of this type of P automata is strictly less than so called restricted logarithmic space Turing machines, and we also exhibit a strict infinite hierarchy within the accepted language class based on the number of membranes present in the system.