Journal of Computer and System Sciences
Membrane systems with coupled transport: universality and normal forms
Fundamenta Informaticae - Membrane computing
The relevance of cell membranes for P Systems: general aspects
Fundamenta Informaticae - Membrane computing
The power of communication: P systems with symport/antiport
New Generation Computing
Simulating Counter Automata by P Systems with Symport/Antiport
WMC-CdeA '02 Revised Papers from the International Workshop on Membrane Computing
On the Number of Non-terminal Symbols in Graph-Controlled, Programmed and Matrix Grammars
MCU '01 Proceedings of the Third International Conference on Machines, Computations, and Universality
P Systems with Proteins on Membranes
Fundamenta Informaticae
Computing with spiking neural p systems: traces and small universal systems
DNA'06 Proceedings of the 12th international conference on DNA Computing
P Systems with Proteins on Membranes
Fundamenta Informaticae
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Symport and antiport are biological ways of transporting molecules through membranes in "collaborating" pairs; in the case of symport the two molecules pass in the same direction, in the case of antiport the two molecules pass in opposite directions. Here we first survey the results about the computing power of membrane systems (P systems) using only symport/antiport rules (hence these systems compute only by using communication), then we introduce a novel way of defining the result of a computation in a membrane system: looking for the trace of certain objects in their movement through membranes. Rather unexpected, in this way we get characterizations of recursively enumerable languages by means of membrane systems with symport/antiport which work with multisets of objects (note the qualitative difference between the data structure used by computations - multisets: no ordering - and the data structure of the output - strings: linear ordering). A similar remark holds true for the case of analysing P systems: the sequence of certain distinguished objects taken from the environment during a computation is the string recognized by the computation. We also survey universality results from this area, with sketched proofs.