Flexibility of measure-Theoretic entropy of boundary maps associated to Fuchsian groups

Adam Abrams, Svetlana Katok, Ilie Ugarcovici

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Given a closed, orientable, compact surface S of constant negative curvature and genus, we study the measure-Theoretic entropy of the Bowen-Series boundary map with respect to its smooth invariant measure. We obtain an explicit formula for the entropy that only depends on the perimeter of the-sided fundamental polygon of the surface S and its genus. Using this, we analyze how the entropy changes in the Teichmüller space of S and prove the following flexibility result: The measure-Theoretic entropy takes all values between 0 and a maximum that is achieved on the surface that admits a regular-sided fundamental polygon. We also compare the measure-Theoretic entropy to the topological entropy of these maps and show that the smooth invariant measure is not a measure of maximal entropy.

Original languageEnglish (US)
Pages (from-to)389-401
Number of pages13
JournalErgodic Theory and Dynamical Systems
Issue number2
StatePublished - Feb 14 2022

All Science Journal Classification (ASJC) codes

  • General Mathematics
  • Applied Mathematics


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