Natural extensions and entropy of α-continued fraction expansions with odd partial quotients

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Authors

External Organisational units

  • TU Delft
  • Sriwijaya University
  • Ohio State University
  • Leiden University

Abstract

n [1], Boca and the fourth author of this paper introduced a new class of continued fraction expansions with odd partial quotients, parameterized by a parameter , where and are the two golden mean numbers. Using operations called singularizations and insertions on the partial quotients of the odd continued fraction expansions under consideration, the natural extensions from [1] are obtained, and it is shown that for each the natural extensions from [1] are metrically isomorphic. An immediate consequence of this is, that the entropy of all these natural extensions is equal for , a fact already observed in [1]. Furthermore, it is shown that this approach can be extended to values of smaller than , and that for values of all natural extensions are still isomorphic. In the final section of this paper further attention is given to the entropy, as function of . It is shown that if there exists an ergodic, absolutely continuous -invariant measure, in any neighborhood of we can find intervals on which the entropy is decreasing, intervals on which the entropy is increasing and intervals on which the entropy is constant. Moreover, we identify the largest interval on which the entropy is constant. In order to prove this we use a phenomenon called matching.

Details

Original languageEnglish
Pages (from-to)2852-2888
Number of pages37
JournalDiscrete and Continuous Dynamical Systems. A
Volume43.2023
Issue number8
DOIs
Publication statusPublished - Aug 2023