: We consider a uniform way of treating objects and rules in P systems: we start with multisets of rules, which are consumed when they are applied, but the application of a rule may also produce rules, to be applied at subsequent steps. We find that this natural and simple feature is surprisingly powerful: systems with only one membrane can characterize the recursively enumerable languages, both in the case of rewriting and of splicing rules; the same result is obtained in the case of symbol-objects, for the recursively enumerable sets of vectors of natural numbers. Key Words: Molecular computing, Membrane computing, Chomsky hierarchy, Rewriting, Splicing
Fernando Arroyo, Angel V. Baranda, Juan Castellano