P Systems with Symport/Antiport of Rules

Moving \instructions" instead of \data", using transport mecha- nisms inspired by biology { this could represent, shortly, the basic idea of the computing device presented in this paper. Speci¯cally, we propose a new class of P systems that use, at the same time, evolution rules and symport/antiport rules. The idea of this kind of systems is simple: during a computation symbol- objects (the \data") evolve using evolution rules but they cannot be moved; on the other hand, the evolution rules (the \instructions") can be moved across the membranes using classical symport/antiport rules. We present di®erent results using di®erent combinations between the power of the evolution rules (catalytic, non-cooperative rules) and the weight of the symport/antiport rules. In particular, we show that, using non-cooperative rules and antiports of un- bounded weight is possible to obtain at least the Parikh set of ET0L languages. On the other hand, using catalytic rules (one catalyst) and antiports of weight 2, the system becomes universal. Several open problems are also presented

P Systems with Antiport Rules for Evolution Rules

We investigate a variant of evolution-communication P systems where the computation is performed in two substeps. First, all possible an- tiport rules are applied in a non-deterministic, maximally parallel way, moving evolution rules across membranes. In the second substep, evolution rules are applied to suitable objects in a maximally parallel way, too. Thus, objects can be the subject of change, but are never moved themselves. As result of a halt- ing computation, we consider the multiset of objects present in a designated output membrane. When using catalytic evolution rules, we already obtain universal computational power with only one catalyst and one membrane. For systems without catalysts we obtain a characterization of the Parikh images of ET0L languages

One-Membrane P Systems with Activation and Blocking of Rules

We introduce new possibilities to control the application of rules based on the preceding applications, which can be de ned in a general way for (hierarchical) P systems and the main known derivation modes. Computational completeness can be obtained even for one-membrane P systems with non-cooperative rules and using both activation and blocking of rules, especially for the set modes of derivation. When we allow the application of rules to in uence the application of rules in previous derivation steps, applying a non-conservative semantics for what we consider to be a derivation step, we can even \go beyond Turing"

P systems with symport/antiport of rules

Moving "instructions" instead of "data" using transport mechanisms inspired by biology is the basic idea of the computing device presented in this paper. Specifically, we propose a new class of P systems that use both evolution rules and symport/antiport rules. The idea of this kind of systems is the following: during a computation, symbol-objects (the "data") evolve using evolution rules, but they cannot be moved; on the other hand, the evolution rules (the "instructions") can be moved across the membranes using classical symport/antiport rules. We present a number of results using different combinations of evolution rules (catalytic, non-cooperative) and the weight of the symport/antiport rules. In particular, we show that using non-cooperative rules and antiports of unbounded weight makes it possible to obtain at least the Parikh set of ETOL languages. On the other hand, using catalytic rules (one catalyst) and antiports of weight 2, these system become universal. Several open problems are also presented. © J.UCS