Looking for Simple Common Schemes to Design Recognizer P Systems with Active Membranes That Solve Numerical Decision Problems

Earlier solutions to decision problems by means of P systems used many counter objects to control the synchronization of different stages in a computation (usually as many counters as the stage must last in the worst case). In this paper we propose a way to replace those counters with some spacial objects for each stage. Furthermore, following the ideas presented in [1], in order to have a common scheme to attack numerical problems, all instances of a problem with the same size are solved by the same P system (which depends on the size) given an input which describes the corresponding instance of the problem. We illustrate these ideas with a cellular solution to the Subset-Sum problem.