We investigate the relationship of time Petri nets and di erent variants of
membrane systems. First we show that the added feature of \time" in time Petri nets
makes it possible to simulate the maximal parallel rule application of membrane systems
without introducing maximal parallelism to the Petri net semantics, then we de ne local
time P systems and explore how time Petri nets and the computations of local time P
systems can be related.
