<?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%">Álvaro Romero-Jiménez</style></author><author><style face="normal" font="default" size="100%">Mario J. Pérez-Jiménez</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Generation of Diophantine Sets by Computing P Systems with External Output</style></title><secondary-title><style face="normal" font="default" size="100%">Lecture Notes in Computer Science</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1007/3-540-45833-6_15</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Springer</style></publisher><pub-location><style face="normal" font="default" size="100%">Amsterdam, The Netherlands</style></pub-location><volume><style face="normal" font="default" size="100%">2509</style></volume><pages><style face="normal" font="default" size="100%">176-190</style></pages><isbn><style face="normal" font="default" size="100%">978-3-540-44311-7</style></isbn><abstract><style face="normal" font="default" size="100%">In this paper a variant of P systems with external output designed to compute functions on natural numbers is presented. These P systems are stable under composition and iteration of functions. We prove that every diophantine set can be generated by such P systems; then, the universality of this model can be deduced from the theorem by Matiyasevich, Robinson, Davis and Putnam in which they establish that every recursively enumerable set is a diophantine set.</style></abstract></record></records></xml>