A1 Refereed original research article in a scientific journal
Recoding Lie algebraic subshifts
Authors: Salo Ville, Törmä Ilkka
Publisher: American Institute of Mathematical Sciences
Publication year: 2021
Journal: Discrete and continuous dynamical systems: series a
Journal name in source: DISCRETE AND CONTINUOUS DYNAMICAL SYSTEMS
Journal acronym: DISCRETE CONT DYN-A
Volume: 41
Issue: 2
First page : 1005
Last page: 1021
Number of pages: 17
ISSN: 1078-0947
eISSN: 1553-5231
DOI: https://doi.org/10.3934/dcds.2020307
Abstract
We study internal Lie algebras in the category of subshifts on a fixed group - or Lie algebraic subshifts for short. We show that if the acting group is virtually polycyclic and the underlying vector space has dense homoclinic points, such subshifts can be recoded to have a cellwise Lie bracket. On the other hand there exist Lie algebraic subshifts (on any finitely-generated non-torsion group) with cellwise vector space operations whose bracket cannot be recoded to be cellwise. We also show that one-dimensional full vector shifts with cellwise vector space operations can support infinitely many compatible Lie brackets even up to automorphisms of the underlying vector shift, and we state the classification problem of such brackets.From attempts to generalize these results to other acting groups, the following questions arise: Does every f.g. group admit a linear cellular automaton of infinite order? Which groups admit abelian group shifts whose homoclinic group is not generated by finitely many orbits? For the first question, we show that the Grigorchuk group admits such a CA, and for the second we show that the lamplighter group admits such group shifts.
We study internal Lie algebras in the category of subshifts on a fixed group - or Lie algebraic subshifts for short. We show that if the acting group is virtually polycyclic and the underlying vector space has dense homoclinic points, such subshifts can be recoded to have a cellwise Lie bracket. On the other hand there exist Lie algebraic subshifts (on any finitely-generated non-torsion group) with cellwise vector space operations whose bracket cannot be recoded to be cellwise. We also show that one-dimensional full vector shifts with cellwise vector space operations can support infinitely many compatible Lie brackets even up to automorphisms of the underlying vector shift, and we state the classification problem of such brackets.From attempts to generalize these results to other acting groups, the following questions arise: Does every f.g. group admit a linear cellular automaton of infinite order? Which groups admit abelian group shifts whose homoclinic group is not generated by finitely many orbits? For the first question, we show that the Grigorchuk group admits such a CA, and for the second we show that the lamplighter group admits such group shifts.
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