The method of forced enumeration for nondeterministic automata
Acta Informatica
Nondeterministic space is closed under complementation
SIAM Journal on Computing
Journal of Computer and System Sciences
Membrane Computing: An Introduction
Membrane Computing: An Introduction
Theoretical Computer Science - Natural computing
The power of communication: P systems with symport/antiport
New Generation Computing
An Application of Dynamic P Systems: Generating Context-Free Languages
WMC-CdeA '02 Revised Papers from the International Workshop on Membrane Computing
Computation: finite and infinite machines
Computation: finite and infinite machines
On determinism versus nondeterminism in P systems
Theoretical Computer Science
On bounded symport/antiport P systems
DNA'05 Proceedings of the 11th international conference on DNA Computing
Computational power of symport/antiport: history, advances, and open problems
WMC'05 Proceedings of the 6th international conference on Membrane Computing
Symbol/Membrane complexity of p systems with symport/antiport rules
WMC'05 Proceedings of the 6th international conference on Membrane Computing
On the computational complexity of P automata
DNA'04 Proceedings of the 10th international conference on DNA computing
Symport/Antiport P Systems with Three Objects Are Universal
Fundamenta Informaticae - Contagious Creativity - In Honor of the 80th Birthday of Professor Solomon Marcus
Computing with cells: membrane systems-some complexity issues
International Journal of Parallel, Emergent and Distributed Systems
The family of languages generated by non-cooperative membrane systems
CMC'10 Proceedings of the 11th international conference on Membrane computing
Infinite hierarchies of conformon-p systems
WMC'06 Proceedings of the 7th international conference on Membrane Computing
Languages in membrane computing: some details for spiking neural p systems
DLT'06 Proceedings of the 10th international conference on Developments in Language Theory
P automata: concepts, results, and new aspects
WMC'09 Proceedings of the 10th international conference on Membrane Computing
A look back at some early results in membrane computing
WMC'09 Proceedings of the 10th international conference on Membrane Computing
P and dp automata: unconventional versus classical automata
DLT'12 Proceedings of the 16th international conference on Developments in Language Theory
On the properties of language classes defined by bounded reaction automata
Theoretical Computer Science
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We give "syntactic" characterizations of context-sensitive languages (CSLs) in terms of some restricted models of symport/antiport P systems. These are the first such characterizations of CSLs in terms of P systems. In particular, we show the following for any language L over a binary alphabet: (1) Let m be any integer ≥ 1. Then L is a CSL if and only if it can be accepted by a restricted symport/antiport P system with m membranes and multiple number of symbols (objects). Moreover, holding the number of membranes at m, there is an infinite hierarchy in computational power (within the class of binary CSLs) with respect to the number of symbols. (2) Let s be any integer ≥ 14. Then L is a CSL if and only if it can be accepted by a restricted symport/antiport P system with s symbols and multiple number of membranes. Moreover, holding the number of symbols at s, there is an infinite hierarchy in computational power with respect to the number of membranes. (Similar results hold for languages over an alphabet of k ≥ 2 symbols.) Thus (1) and (2) say that in order for the restricted symport/antiport P systems to accept all binary CSLs, at least one parameter (either the number of symbols or the number of membranes) must grow. These are the first results of their kind in the P systems area. They contrast a known result that (unrestricted) symport/antiport P systems with s ≥ 2 symbols and m ≥ 1 membranes accept (or generate) exactly the recursively enumerable sets of numbers even for s + m = 6. We also note that previous characterizations of formal languages in the membrane computing literature are mostly for the Parikh images of languages.Variations of our model yield characterizations of regular languages, languages accepted by one-way log n space-bounded Turing machines, and recursively enumerable languages.