G. Paun and S. Yu
Abstract:
The P systems were recently introduced as
distributed parallel computing models of a biochemical type. Multisets of obje
cts
are placed in a hierarchical structure of membranes and they evolve according
to
given rules, which are applied in a synchronous manner: at each step, all
objects which can evolve, from all membranes, must evolve. We consider here th
e
case when this restriction is removed. As expected, unsynchronized systems
(even using catalysts) are
weaker than the synchronized ones, providing that no priority relation among r
ules
is considered. The power of P systems is not diminished when a priority is
used and, moreover, the catalysts can change their states, among two possible
states for each catalyst.