Title
Amenability of groups is characterized by Myhill's theorem
Abstract
We prove a converse to Myhill's "Garden-of-Eden" theorem and obtain in this manner a characterization of amenability in terms of cellular automata: A group G is amenable if and only if every cellular automaton with carrier G that has gardens of Eden also has mutually erasable patterns. This answers a question by Schupp, and solves a conjecture by Ceccherini-Silberstein, Machi and Scarabotti. Furthermore, for non-amenable G the cellular automaton with carrier G that has gardens of Eden but no mutually erasable patterns may also be assumed to be linear. An appendix by Dawid Kielak shows that group rings without zero divisors are Ore domains precisely when the group is amenable, answering a conjecture attributed to Guba.
Year
DOI
Venue
2016
10.4171/JEMS/900
JOURNAL OF THE EUROPEAN MATHEMATICAL SOCIETY
Keywords
Field
DocType
Cellular automata,Moore-Myhill theorem,amenability of groups,Ore domains,localization
Cellular automaton,Discrete mathematics,Group rings,Converse,Combinatorics,Zero divisor,If and only if,Conjecture,Mathematics
Journal
Volume
Issue
ISSN
21
10
1435-9855
Citations 
PageRank 
References 
0
0.34
0
Authors
2
Name
Order
Citations
PageRank
Laurent Bartholdi1278.74
Dawid Kielak200.68