%0 Generic
%D 2006
%T On the branching complexity of P systems
%A Gabriel Ciobanu
%A Gheorghe Paun
%A Mario J. Pérez-Jiménez
%C Amsterdam, Holanda
%I IOS Press
%K decidability
%K descriptional complexity
%K Membrane computing
%K non-determinism
%N 1-2
%P 27-36
%U http://portal.acm.org/citation.cfm?id=1231163
%V 73
%X We consider two complexity parameters related to the graph of reachable configurations of a given P system, namely the outdegree as a measure of the degree of non-determinism, and the indegree as a measure of the degree of confluence. These parameters can be defined for both the generative and the accepting mode of using a P system. We investigate here these parameters in what concerns hierarchies and decidability issues. We prove that all hierarchies have only two levels and that all considered decidability problems have a negative answer.