English

Conjugacy for certain automorphisms of the one-sided shift via transducers

Group Theory 2024-07-29 v2 Formal Languages and Automata Theory Dynamical Systems

Abstract

We address the following open problem, implicit in the 1990 article "Automorphisms of one-sided subshifts of finite type" of Boyle, Franks and Kitchens (BFK): "Does there exists an element ψ\psi in the group of automorphisms of the one-sided shift Aut({0,1,,n1}N,σn)\operatorname{Aut}(\{0,1,\ldots,n-1\}^{\mathbb{N}}, \sigma_{n}) so that all points of {0,1,,n1}N\{0,1,\ldots,n-1\}^{\mathbb{N}} have orbits of length nn under ψ\psi and ψ\psi is not conjugate to a permutation?" Here, by a 'permutation' we mean an automorphism of one-sided shift dynamical system induced by a permutation of the symbol set {0,1,,n1}\{0,1,\ldots,n-1\}. We resolve this question by showing that any ψ\psi with properties as above must be conjugate to a permutation. Our techniques naturally extend those of BFK using the strongly synchronizing automata technology developed here and in several articles of the authors and collaborators (although, this article has been written to be largely self-contained).

Keywords

Cite

@article{arxiv.2301.13570,
  title  = {Conjugacy for certain automorphisms of the one-sided shift via transducers},
  author = {Collin Bleak and Feyishayo Olukoya},
  journal= {arXiv preprint arXiv:2301.13570},
  year   = {2024}
}

Comments

40 pages, 9 Figures. This new version simplifies the exposition and proof approach. Some of the relabelling lemmas have been replaced by more targeted and "slimmed" down versions. We are grateful to an anonymous referee for detailed and very helpful comments on an earlier draft of the article