Complexity aspects of polarizationless membrane systems

We investigate polarizationless P systems with active membranes working in maximally parallel manner, which do not make use of evolution or communication rules, in order to find which features are sufficient to efficiently solve computationally hard problems. We show that such systems are able to solve the PSPACE-complete problem Quantified 3-sat, provided that non-elementary membrane division is controlled by the presence of a (possibly non-elementary) membrane. © 2008 Springer Science+Business Media B.V