<?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%">Alberto Leporati</style></author><author><style face="normal" font="default" size="100%">Claudio Ferretti</style></author><author><style face="normal" font="default" size="100%">Giancarlo Mauri</style></author><author><style face="normal" font="default" size="100%">Mario J. Pérez-Jiménez</style></author><author><style face="normal" font="default" size="100%">Claudio Zandron</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Complexity aspects of polarizationless membrane systems</style></title><secondary-title><style face="normal" font="default" size="100%">Natural Computing</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">12/2009</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/content/a8q346311328p807/</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Springer Verlag</style></publisher><pub-location><style face="normal" font="default" size="100%">Amsterdam, Netherlands</style></pub-location><volume><style face="normal" font="default" size="100%">8</style></volume><pages><style face="normal" font="default" size="100%">703-717</style></pages><abstract><style face="normal" font="default" size="100%">We investigate polarizationless P systems with active membranes working in maximally parallel manner, which do not make use of evolution or communication rules, in order to find which features are sufficient to efficiently solve computationally hard problems. We show that such systems are able to solve the PSPACE-complete problem Quantified 3-sat, provided that non-elementary membrane division is controlled by the presence of a (possibly non-elementary) membrane.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue></record></records></xml>