This paper analyses several problems related to finding and counting ancestor and descendant states, as well as gardens of Eden (i.e., states without predecessors) in reaction systems. The focus is on the complexity of finding and counting preimages and ancestors that are minimal with respect to cardinality. It turns out that the problems concerning gardens of Eden seem to require the presence ...

One of the first and most famous results of cellular automata theory, Moore’s Garden-of-Eden theorem has been proven to hold if and only if the underlying group possesses the measure-theoretic properties suggested by von Neumann to be the obstacle to the Banach-Tarski paradox. We show that several other results from the literature, already known to characterize surjective cellular automata in d...

c © 2006 by John von Neumann Institute for Computing Permission to make digital or hard copies of portions of this work for personal or classroom use is granted provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise requires prior specific permission by the publisher ment...

Parallelism has always been a hidden main source of processor power. As a result of the limited amount of implicitly exploitable small-scale parallelism (for example on the instruction-level) and ever-growing needs for more computational power, parallel techniques break their way from a minor matter to a major feature in both hardware and software. Due to their complexity, such parallel systems...

c © 2006 by John von Neumann Institute for Computing Permission to make digital or hard copies of portions of this work for personal or classroom use is granted provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise requires prior specific permission by the publisher ment...