English

Lamplighters admit weakly aperiodic SFTs

Group Theory 2018-02-05 v2 Dynamical Systems

Abstract

Let AA be a finite set and GG a group. A closed subset XX of AGA^G is called a subshift if the action of GG on AGA^G preserves XX. If KK is a closed subset of AGA^G such that membership in KK is determined by looking at a fixed finite set of coordinates, and XX is the intersection of all translates of KK under the action of GG, then XX is called a subshift of finite type (SFT). If an SFT is nonempty and contains no finite GG-orbits, it is said to be weakly aperiodic. A virtually cyclic group has no weakly aperiodic SFT, and Carroll and Penland have conjectured that a group with no weakly aperiodic SFT must be virtually cyclic. Answering a question of Jeandel, we show that lamplighters always admit weakly aperiodic SFTs.

Keywords

Cite

@article{arxiv.1710.03707,
  title  = {Lamplighters admit weakly aperiodic SFTs},
  author = {David Bruce Cohen},
  journal= {arXiv preprint arXiv:1710.03707},
  year   = {2018}
}

Comments

10 pages, 3 figures have been added, some corrections have been made

R2 v1 2026-06-22T22:09:08.094Z