Complexity classes in models of cellular computing with membranes

In this paper we introduce four complexity classes for cellularcomputing systems with membranes: the first and the second ones containall decision problems solvable in polynomial time by a family ofdeterministic P systems, without and with an input membrane,respectively; the third and fourth classes contain all decision problemssolvable in polynomial time by a family of non-deterministic P systems,without and with an input membrane, respectively. We illustrate theusefulness of these classes by solving two NP-completeproblems, namely HPP and SAT, in both variants of Psystems.[PUBLICATION ABSTRACT]