English

Finite entropy for multidimensional cellular automata

Dynamical Systems 2007-06-13 v3

Abstract

Let X=SGX=S^G where GG is a countable group and SS is a finite set. A cellular automaton (CA) is an endomorphism T:XXT : X \to X (continuous, commuting with the action of GG). Shereshevsky (1993) proved that for G=ZdG=Z^d with d>1d>1 no CA can be forward expansive, raising the following conjecture: For G=ZdG=Z^d, d>1d>1 the topological entropy of any CA is either zero or infinite. Morris and Ward (1998), proved this for linear CA's, leaving the original conjecture open. We show that this conjecture is false, proving that for any dd there exist a dd-dimensional CA with finite, nonzero topological entropy. We also discuss a measure-theoretic counterpart of this question for measure-preserving CA's. Our main tool is a construction of a CA by Kari (1994).

Keywords

Cite

@article{arxiv.math/0703167,
  title  = {Finite entropy for multidimensional cellular automata},
  author = {Tom Meyerovitch},
  journal= {arXiv preprint arXiv:math/0703167},
  year   = {2007}
}

Comments

17 pages, 11 figures; Added references, proposition 3.5 and correction of minor mistake in section 2