Results on catalytic and evolution-communication P systems

In this paper we give several improved universality results for two important classes of P systems: P systems with catalysts and evolution-communication P systems. First, the result from Reference,(14)) stating that si-x catalysts ensure the universality, has been improved in two ways: using bistable catalysts and using moving catalysts. Specifically, the universality can be reached with one bistable catalyst and 2 usual catalysts (using five membranes), as well as with one moving catalyst and three membranes, or with two moving catalysts and only two membranes. The second part of the paper deals with evolution-communication P systems, and we also give improved universality results for this type of systems, in terms of the weight, of symport/antiport rules, number of membranes, or number of catalysts