<?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%">Paolo Bottoni</style></author><author><style face="normal" font="default" size="100%">Anna Labella</style></author><author><style face="normal" font="default" size="100%">Carlos Martín-Vide</style></author><author><style face="normal" font="default" size="100%">Gheorghe Paun</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Rewriting P Systems with Conditional Communication </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://www.springerlink.com/index/B69VXGXMY73WD34R.pdf</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%">2300</style></volume><pages><style face="normal" font="default" size="100%">325-353</style></pages><abstract><style face="normal" font="default" size="100%">A membrane system (P system) is a model of computation inspired by some basic features of the structure and behaviour of living cells. In this paper we consider systems with string-objects processed by rewriting, with the communication controlled by conditions on the contents of the strings. Symbols, substrings (in an arbitrary place, or as a prefix/suffix), or the shape of the whole string are used as permitting and as forbidding conditions when moving strings from a membrane to a neighboring membrane. Many of the obtained variants lead to new characterizations of recursively enumerable languages (as expected, these characterizations indicate a trade-off between the number of membranes and the strength of the communication conditions used). Several open problems are also formulated.
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