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  Editors-in-chief: C. A. Athanasiadis, T. Lam, A. Munemasa, H. Van Maldeghem
ISSN 0925-9899 (print) • ISSN 1572-9192 (electronic)

Dynamics groups of asynchronous cellular automata

Matthew Macauley , Jon McCammond and Henning S. Mortveit

DOI: 10.1007/s10801-010-0231-y


We say that a finite asynchronous cellular automaton (or more generally, any sequential dynamical system) is π -independent if its set of periodic points are independent of the order that the local functions are applied. In this case, the local functions permute the periodic points, and these permutations generate the dynamics group. We have previously shown that exactly 104 of the possible 2 2 3=256 2^{2^{3}}=256 cellular automaton rules are π -independent. In the article, we classify the periodic states of these systems and describe their dynamics groups, which are quotients of Coxeter groups. The dynamics groups provide information about permissible dynamics as a function of update sequence and, as such, connect discrete dynamical systems, group theory, and algebraic combinatorics in a new and interesting way. We conclude with a discussion of numerous open problems and directions for future research.

Pages: 11–35

Keywords: keywords sequential dynamical systems; cellular automata; update order; dynamics groups; Coxeter groups; periodic points; Fibonacci numbers; Lucas numbers

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