Symport/Antiport P Systems with Three Objects Are Universal

Abstract

The operations of symport and antiport, directly inspired from biology, are already known to be rather powerful when used in the framework of P systems. In this paper we confirm this observation with a quite surpris- ing result: P systems with symport/antiport rules using only three objects can simulate any counter machine, while systems with only two objects can simulate any blind counter machine. In the first case, the universality (of gen- erating sets of numbers) is obtained also for a small number of membranes, four.