<?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%">Miguel A. Gutiérrez-Naranjo</style></author><author><style face="normal" font="default" size="100%">Mario J. Pérez-Jiménez</style></author><author><style face="normal" font="default" size="100%">Agustín Riscos-Núñez</style></author><author><style face="normal" font="default" size="100%">Francisco J. Romero-Campero</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Computational efficiency of dissolution rules in membrane systems</style></title><secondary-title><style face="normal" font="default" size="100%">International Journal of Computer Mathematics</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Computational efficiency; Dissolution rules; Membrane systems</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://www.informaworld.com/smpp/content~content=a769606660~db=all~order=page</style></url></web-urls><related-urls><url><style face="normal" font="default" size="100%">http://www.gcn.us.es/files/Computational Efficiency.pdf</style></url></related-urls></urls><pub-location><style face="normal" font="default" size="100%">Londres</style></pub-location><volume><style face="normal" font="default" size="100%">83</style></volume><pages><style face="normal" font="default" size="100%">593-611</style></pages><abstract><style face="normal" font="default" size="100%">Trading (in polynomial time) space for time in the framework of membrane systems is not sufficient to efficiently solve computationally hard problems. On the one hand, an exponential number of objects generated in polynomial time is not sufficient to solve NP-complete problems in polynomial time. On the other hand, when an exponential number of membranes is created and used as workspace, the situation is very different. Two operations in P systems (membrane division and membrane creation) capable of constructing an exponential number of membranes in linear time are studied in this paper. NP-complete problems can be solved in polynomial time using P systems with active membranes and with polarizations, but when electrical charges are not used, then dissolution rules turn out to be very important. We show that in the framework of P systems with active membranes but without polarizations and in the framework of P systems with membrane creation, dissolution rules play a crucial role from the computational efficiency point of view.</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue></record></records></xml>