Affiliations: Institute of Mathematics of the Romanian Academy, PO
Box 1-764, 014700 Bucureşti, Romania. george.paun@imar.ro | Research Group on Natural Computing, Department of
Computer Science and Artificial Intelligence, University of Sevilla, Avda.
Reina Mercedes s/n, 41012 Sevilla, Spain. gpaun/marper@us.es | Department of Artificial Intelligence, Faculty of
Computer Science, Polytechnical University of Madrid, Campus de Montegancedo,
Boadilla del Monte 28660, Madrid, Spain. jpazos/arpaton@fi.upm.es
Note: [] Address for correspondence: Institute of Mathematics of the
Romanian Academy, PO Box 1-764, 014700 Bucureşti, Romania
Abstract: The operations of symport and antiport, directly inspired
frombiology, are already known to be rather powerful when used in the framework
of P systems. In this paper we confirm this observation with a quite surprising
result: P systems with symport/antiport rules using only three objects can
simulate any counter machine, while systems with only two objects can simulate
any blind counter machine. In the first case, the universality (of generating
sets of numbers) is obtained also for a small number of membranes, four.
