Freeness of automaton groups vs boundary dynamics

Daniele D'Angeli, Emanuele Rodaro*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We prove that the boundary dynamics of the (semi)group generated by the enriched dual transducer characterizes the algebraic property of being free for an automaton group. We specialize this result to the class of bireversible transducers and we show that the property of being not free is equivalent to the existence of a finite Schreier graph in the boundary of the enriched dual pointed at some essentially non-trivial point. From these results we derive some consequences from the algebraic, algorithmic and dynamical points of view.

Original languageEnglish
Pages (from-to)115-136
Number of pages22
JournalJournal of Algebra
Publication statusPublished - 15 Sept 2016


  • Automaton groups
  • Boundary actions
  • Essentially free actions
  • Schreier graphs

ASJC Scopus subject areas

  • Algebra and Number Theory


Dive into the research topics of 'Freeness of automaton groups vs boundary dynamics'. Together they form a unique fingerprint.

Cite this