English

A Renormalization Scheme for Semi-Regular Continued Fractions

Dynamical Systems 2023-02-03 v1

Abstract

In this article we study a renormalization scheme with which we find all semi-regular continued fractions of a number in a natural way. We define two maps, T_slow and T_fast: these maps are defined for (x,y) in [0,1], where x is the number for which a semi-regular continued fraction representation is developed by T_slow according to the parameter y. The set of all possible semi-regular continued fraction representations of x are bijectively constructed as the parameter y varies. The map T_fast is a "sped-up" version of the map T_slow, and we show that T_fast is ergodic with respect to a probability measure which is mutually absolutely continuous with Lebesgue measure. In contrast, T_slow preserves no such measure, but does preserve an infinite, sigma-finite measure mutually absolutely continuous with Lebesgue measure. Furthermore, we generate a sequence of substitutions which generate a symbolic coding of the orbit of y. In the last section we highlight how our scheme can be used to generate semi-regular continued fractions explicitly for specific continued fraction algorithms such as Nakada's alpha continued fractions.

Keywords

Cite

@article{arxiv.2302.00945,
  title  = {A Renormalization Scheme for Semi-Regular Continued Fractions},
  author = {Niels Langeveld and David Ralston},
  journal= {arXiv preprint arXiv:2302.00945},
  year   = {2023}
}
R2 v1 2026-06-28T08:30:00.779Z