<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>13</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gheorghe Paun</style></author><author><style face="normal" font="default" size="100%">Radu  Paun</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Membrane Computing and Economics: Numerical P Systems</style></title><secondary-title><style face="normal" font="default" size="100%">Fundamenta Informaticae</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">economics</style></keyword><keyword><style  face="normal" font="default" size="100%">Membrane computing</style></keyword><keyword><style  face="normal" font="default" size="100%">Turing computability</style></keyword><keyword><style  face="normal" font="default" size="100%">Universality</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://portal.acm.org/citation.cfm?id=1231159.1231179&coll=GUIDE&dl=GUIDE&CFID=1691426&CFTOKEN=24108515</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">IOS Press</style></publisher><pub-location><style face="normal" font="default" size="100%">Warsaw, Poland</style></pub-location><volume><style face="normal" font="default" size="100%">73</style></volume><pages><style face="normal" font="default" size="100%">213-227</style></pages><abstract><style face="normal" font="default" size="100%">With inspiration from the economic reality, where numbers are basic entities to work with, we propose a genuinely new kind of P systems, where numerical variables evolve, starting from initial values, by means of production functions and repartition protocols. We prove that non-deterministic systems of this type, using polynomial production functions, characterize the Turing computable sets of natural numbers, while deterministic systems, with polynomial production functions having non-negative coefficients, compute strictly more than semilinear sets of natural numbers. A series of research topics to be addressed in this framework are mentioned.

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