Formal languages
Journal of Computer and System Sciences
Regulated Rewriting in Formal Language Theory
Regulated Rewriting in Formal Language Theory
Membrane Computing: An Introduction
Membrane Computing: An Introduction
Fundamenta Informaticae - Membrane computing
A Survey of Some Variants of P Systems
WMC-CdeA '02 Revised Papers from the International Workshop on Membrane Computing
Rewriting P systems with conditional communication
Formal and natural computing
On three variants of rewriting P systems
Theoretical Computer Science
P Systems with Mobile Membranes
Natural Computing: an international journal
| Hi-index | 5.23 |
Generally, for proving universality results about rewriting P systems one considers matrix grammars in the strong binary normal form. Such grammars contain both matrices with rules used in the appearance checking mode and matrices without appearance checking rules. In the proofs of most of the universality theorems reported in the literature, appearance checking matrices are simulated by using only two membranes, while four membranes are used for simulating matrices without appearance checking rules. Thus, a way to improve these theorems is to diminish the number of membranes used for simulating matrices without appearance checking rules. In this paper we address this problem, and give first a general improved result about simulating matrix grammars without appearance checking: three membranes are shown to suffice. This result is then used to improve several universality results from various membrane computing papers, for instance, about P systems with replicated rewriting, with leftmost rewriting, with conditional communication, as well as for hybrid P systems with finite choice.