POPL '90 Proceedings of the 17th ACM SIGPLAN-SIGACT symposium on Principles of programming languages
Journal of Computer and System Sciences
Introduction to Automata Theory, Languages and Computability
Introduction to Automata Theory, Languages and Computability
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
Membrane Computing: When Communication Is Enough
UMC '02 Proceedings of the Third International Conference on Unconventional Models of Computation
Catalytic P systems, semilinear sets, and vector addition systems
Theoretical Computer Science
On the computational complexity of membrane systems
Theoretical Computer Science
Context-free languages can be accepted with absolutely no space overhead
Information and Computation
Context-free languages can be accepted with absolutely no space overhead
Information and Computation
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
On symport/antiport p systems and semilinear sets
WMC'05 Proceedings of the 6th international conference on Membrane Computing
Some computational issues in membrane computing
MFCS'05 Proceedings of the 30th international conference on Mathematical Foundations of Computer Science
Conformon p systems and topology of information flow
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
On Restricted Bio-Turing Machines
Fundamenta Informaticae - Theory that Counts: To Oscar Ibarra on His 70th Birthday
Hi-index | 5.23 |
We look at a restricted model of a communicating P system, called RCPS, whose environment does not contain any object initially. The system can expel objects into the environment but only expelled objects can be retrieved from the environment. Such a system is initially given an input a1i1 ... anin (with each ij representing the multiplicity of distinguished object ai, 1≤i≤n) and is used as an acceptor. We show that RCPSs are equivalent to two-way multihead finite automata over bounded languages (i.e., subsets of a1* ... an*, for some distinct symbols a1 ..... an). We then show that there is an infinite hierarchy of RCPS's in terms of the number of membranes: For every r, there is an s r and a unary language L accepted by an RCPS with s membranes that cannot be accepted by an RCPS with r membranes. This provides an answer to an open problem in (Membrane Computing: An Introduction, Springer, Berlin, 2002) which asks whether there is a nonuniversal model of a membrane computing system which induces an infinite hierarchy on the number of membranes. We also consider variants/generalizations of RCPSs, e.g, acceptors of languages; models that allow a "polynomial bounded" supply of objects in the environment initially; models with tentacles, etc. We show that they also form an infinite hierarchy with respect to the number of membranes (or tentacles). The proof techniques can be used to obtain similar results for other restricted models of P systems, like symport/antiport systems.