FREUND , Rudolf

Purely catalytic P systems can generate all recursively enumerable sets of natural numbers with only three catalysts in one membrane, whereas we know that one catalyst in one membrane is not enough. On the other hand, P systems also allowing (non-catalytic) non-cooperative evolution rules with only two catalysts in one membrane are already...

In the area of P systems, besides the standard maximally parallel derivation mode, many other derivation modes have been investigated, too. In this paper, many variants of hierarchical P systems and tissue P systems using different derivation modes are considered and the effects of using di erent derivation modes, especially the...

P systems with active membranes but without using electrical charges (polarizations) are shown to be complete for generating recursively enumerable string languages when working on string objects and using only rules with membrane transitions as well as rules with membrane dissolving and elementary membrane division, but also when using various...

The aim of this paper is to study the computational power of P systems with one active membrane without polarizations. For P systems with active membranes, it is known that computational completeness can be obtained with either of the following combinations of features: 1)two polarizations, 2)membrane creation and dissolution, 3)four membranes...

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...

We consider (tissue) P systems using non-cooperative rules, but considering computations without halting conditions. As results of a computation we take the contents of a specified output membrane/cell in each derivation step, no matter whether this computation will ever halt or not, eventually taking only results completely consisting of...

We consider P systems with only one membrane using symport/antiport rules and prove that any recursively enumerable set of k-dimensional vectors of natural numbers can be generated (accepted) by using at most k + 4 symbols; hence, any recursively enumerable set of natural numbers can be generated (accepted) by using at most five symbols.

Membrane systems (with symbol objects) are distributed controlled multiset processing systems. Non-cooperative P systems with either promoters or inhibitors (of weight not restricted to one) are known to be computationally complete. In this paper we show that the power of the deterministic subclass of such systems is computationally complete in...

Based on the construction of a universal register machine we construct a universal antiport P system working with 31 rules in the maximally parallel mode in one membrane, and a universal antiport P system with forbidden context working with 16 rules in the sequential derivation mode in one membrane for computing any partial recursive function...

Whether P systems with only one catalyst can already be universal, is still an open problem. Here we establish universality (computational completeness) by using speci c variants of additional control mechanisms. At each step using only multiset rules from one set of a nite number of sets of rules allows for obtaining computational...