127 research outputs found
P Systems with Symport/Antiport of Rules
Moving \instructions" instead of \data", using transport mecha-
nisms inspired by biology { this could represent, shortly, the basic idea of the
computing device presented in this paper. Speci¯cally, we propose a new class
of P systems that use, at the same time, evolution rules and symport/antiport
rules. The idea of this kind of systems is simple: during a computation symbol-
objects (the \data") evolve using evolution rules but they cannot be moved; on
the other hand, the evolution rules (the \instructions") can be moved across
the membranes using classical symport/antiport rules. We present di®erent
results using di®erent combinations between the power of the evolution rules
(catalytic, non-cooperative rules) and the weight of the symport/antiport rules.
In particular, we show that, using non-cooperative rules and antiports of un-
bounded weight is possible to obtain at least the Parikh set of ET0L languages.
On the other hand, using catalytic rules (one catalyst) and antiports of weight
2, the system becomes universal. Several open problems are also presented
Membrane fission versus cell division: When membrane proliferation is not enough
Cell division is a process that produces two or more cells from one cell by replicating the original chromosomes so that each daughter cell gets a copy of them. Membrane fission is a process by which a biological membrane is split into two new ones in suchamanner that the contents of the initial membrane get distributedor separated among the new membranes. Inspired by these biological phenomena, new kinds of models we reconsidered in the discipline of Membrane Computing, in the context of P systems with active membranes, and tissue P systems that use symport/antiport rules, respectively.
This paper combines the two approaches: cell-like P systems with symport/antiport rules and membrane separation are studied, from a computational complexity perspective.Specifically, the role of the environment in the context of cell-like P systems withmembrane separation is established, and additional borderlines between tractability and NP-hardness are summarized.Ministerio de Economía y Competitividad TIN2012- 3743
P systems with symport/antiport rules: When do the surroundings matter?
Cell-like P systems where communication between the regions are carried out by rules of type symport/antiport are considered. These systems compute by changing the places of objects with respect to the membranes, and not by changing the objects themselves. The environment plays an active role in the sense that it not only can receive objects from the system, but also send objects into it. There is an alphabet associated with the environment whose elements appear in an arbitrary large number of copies at the initial configuration. This property seems too strong from a complexity view, but it has been widely exploited in the design of efficient solutions to computationally hard problems when some mechanisms (inspired by mitosis and membrane fission) allowing to construct an exponential workspace in linear time, are considered. In this paper, complexity aspects of P systems with symport/antiport rules and membrane division are considered when the set associated with the environment is the emptyset. It is shown that the role of the environment is irrelevant for such kind of P systems, in contrast with the well known results concerning to its relevance when membrane separation is used instead of membrane division.Ministerio de Economía y Competitividad TIN2017-89842-PNational Natural Science Foundation of China 6132010600
Limits on Efficient Computation in P Systems with Symport/Antiport Rules
Classical membrane systems with symport/antiport rules observe the con-
servation law, in the sense that they compute by changing the places of objects with
respect to the membranes, and not by changing the objects themselves. In these systems
the environment plays an active role because the systems not only send objects to the
environment, but also bring objects from the environment. In the initial configuration of
a system, there is a special alphabet whose elements appear in an arbitrary large number
of copies. The ability of these computing devices with infinite copies of some objects has
been widely exploited in the design of efficient solutions to computationally hard problems.
This paper deals with computational aspects of P systems with symport/antiport
rules and membrane division rules or membrane separation rules. Specifically, we study
the limitations of such P systems when the only communication rules allowed have length
1.Ministerio de Ciencia e Innovación TIN2012-3743
Minimal Cooperation in P Systems with Symport/Antiport: A Complexity Approach
Membrane systems with symport/antiport rules compute by just moving
objects among membranes, and not by changing the objects themselves. In these systems
the environment plays an active role because, not only it receives objects from the system,
but it also sends objects into the system. Actually, in this framework it is commonly
assumed that an arbitrarily large number of copies of some objects are initially available
in the environment. This special feature has been widely exploited for the design of
e cient solutions to computationally hard problems in the framework of tissue like P
systems able to create an exponential workspace in polynomial time (e.g. via cell division
or cell separation rules).
This paper deals with cell-like P systems which use symport/antiport rules as communication
rules, and the role played by the minimal cooperation is studied from a computational
complexity point of view. Speci cally, the limitations on the e ciency of P systems
with membrane separation whose symport/antiport rules involve at most two objects are
established. In addition, a polynomial time solution to HAM-CYCLE problem, a well known
NP-complete problem, by using a family of such kind of P systems with membrane
division, is provided. Therefore, in the framework of cell-like P systems with minimal
cooperation in communication rules, passing from membrane separation to membrane
division amounts to passing from tractability to NP{hardness.Ministerio de Economía y Competitividad TIN2012-3743
Small Universal Tissue P Systems with Symport/Antiport Rules
In this note, we consider the problem of looking for small universal one-symbol tissue P systems with symport/antiport rules. It is proved that six cells suffice to generate any recursively enumerable set of natural numbers by such a onesymbol tissue P system with symport/antiport rules, under the restriction that only one channel is allowed between two cells or between a cell and the environment. As for the case of allowing two channels between a cell and the environment, it is shown that the computational completeness can be obtained by one-symbol tissue P systems with symport/antiport rules having at most five cells. These results partially answer an open problem formulated by Artiom Alhazov, Rudolf Freund and Marion Oswald
Further Remarks on Trace Languages in P Systems with Symport/Antiport
P systems are parallel molecular computing models which process multisets
of objects in cell-like membrane structures. In this paper we consider the trace languages
of a special symbol, the traveler, in symport/antiport P systems where, instead of multisets of objects, sets of objects were considered. Two different ways to define the trace
language are proposed. One of the families of languages obtained in this way is proved
to be equal to the family of regular languages and the other one to be strictly smaller.
Some ideas for further research are also considered
P and dP Automata: A Survey
This is a quick survey of basic notions and results related to P automata (P systems with symport/antiport rules working in the accepting mode), with some emphasis on the recently introduced dP automata (a distributed version of the standard P automata), ending with some open problems and research topics which we find of interest in this area.Junta de Andalucía P08 – TIC 0420
On Efficiency of P Systems with Symport/Antiport and Membrane Division
Classical membrane systems with symport/antiport rules observe the con-
servation law, in the sense that they compute by changing the places of objects with
respect to the membranes, and not by changing the objects themselves. In these systems
the environment plays an active role because the systems not only send objects to the
environment, but also bring objects from the environment. In the initial configuration of
a system, there is a special alphabet whose elements appear in an arbitrary large number
of copies. The ability of these computing devices to have infinite copies of some objects
has been widely exploited in the design of efficient solutions to computationally hard
problems.
This paper deals with computational aspects of P systems with symport/antiport
and membrane division rules where there is not an environment having the property
mentioned above. Specifically, we establish the relationships between the polynomial
complexity class associated with P systems with symport/antiport, membrane division
rules, and with or without environment. As a consequence, we prove that the role of the
environment is irrelevant in order to solve NP–complete problems in an efficient way.Ministerio de Ciencia e Innovación TIN2012-3743
Membrane Fission: A Computational Complexity Perspective
Membrane fission is a process by which a biological membrane is split into two new ones in the manner
that the content of the initial membrane is separated and distributed between the new membranes. Inspired by this
biological phenomenon, membrane separation rules were considered in membrane computing. In this work, we
investigate cell-like P systems with symport/antiport rules and membrane separation rules from a computational
complexity perspective. Specifically, we establish a limit on the efficiency of such P systems which use communication
rules of length at most two, and we prove the computational efficiency of this kind of models when using
communication rules of length at most three. Hence, a sharp borderline between tractability and NP–hardness
is provided in terms of the length of communication rules.Ministerio de Economía y Competitividad TIN2012-3743
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