Decidability of Divergence for Catalytic P Systems

P systems are a biologically inspired model introduced by Gheorghe P¸aun with the aim of representing the structure and the functioning of the cell. Since their introduction, several variants of P systems have been proposed and explored. We concentrate on the class of catalytic P systems without priorities associated to the rules. We show that the divergence problem (i.e., checking for the existence of an infinite computation) is decidable in such a class of P systems. As a corollary, we obtain an alternative proof of the nonuniversality of deterministic catalytic P systems, an open problem recently solved by Ibarra and Yen

On the Expressiveness of Movement in Pure Mobile Ambients

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On the Serializability of Transactions in JavaSpaces

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Some Notes on (Mem)Brane Computation

Membrane Computing and Brane Calculi are two recent computational paradigms in the framework of Natural Computing. They are based on the study of the structure and functioning of living cells as living organisms able to process and generate information. In this paper we give a short introduction to both areas and point out some open research lines.Ministerio de Educación y Ciencia TIN2005-09345-C04-01Junta de Andalucía TIC-58

A Case Study in (Mem)Brane Computation: Generating {n2 | n 1}

The aim of this paper is to start an investigation and a comparison of the expressiveness of the two most relevant formalisms inspired by membranes interactions, namely, P systems and Brane Calculi. We compare the two formalisms w.r.t. their ability to act as language generators. In particular, we show different ways of generating the set L = {n2 | n 1} in P systems and in Brane Calculi.Ministerio de Educación y Ciencia TIC2002-04220-C03-0

A Case Study in (Mem)Brane Computation: Generating Squares of Natural Numbers

The aim of this paper is to start an investigation and a comparison of the expressiveness of the two most relevant formalisms inspired by membranes interactions, namely, P systems and Brane Calculi. We compare the two formalisms with respect to their ability to act as generator devices. In particular, we show different ways of generating the set L = {n2 | n ≥ 1} in P systems and in Brane Calculi.Ministerio de Educación y Ciencia TIN2005-09345-C03-01Junta de Andalucía TIC-58

SecSpaces: a Data-driven Coordination Model for Environments Open to Untrusted Agent∗

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Two Universality Results for (Mem)Brane Systems

We prove that P systems with mate and drip operations and using at most five membranes during any step of a computation are universal. This improves a recent similar result from, where eleven membranes are used. The proof of this result has the "drawback" that the output of a computation is obtained on an inner membrane of the system. A universality proof is then given for the case when the result of a computation is found on the skin membrane (on its external side, hence "visible" from the environment), but in this case we use one more membrane, as well as another basic brane operation exo; moreover, the operations are now of the projective type, as introduced in

Efficient computation in rational-valued P systems

In this paper, we describe a new representation for deterministic rational-valued P systems that allows us to form a bridge between membrane computing and linear algebra. On the one hand, we prove that an efficient computation for these P systems can be described using linear algebra techniques. In particular, we show that the computation for getting a configuration in such P systems can be carried out by multiplying appropriate matrices. On the other hand, we also show that membrane computing techniques can be used to get the nth power of a given matrix.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía TIC-58