English

Infinite products related to generalized Thue-Morse sequences

Number Theory 2020-06-09 v1

Abstract

Given an integer q2q\ge2 and θ1,,θq1{0,1}\theta_1,\cdots,\theta_{q-1}\in\{0,1\}, let (θn)n0(\theta_n)_{n\ge0} be the generalized Thue-Morse sequence, defined to be the unique fixed point of the morphism 00θ1θq10\mapsto0\theta_1\cdots\theta_{q-1} 11θ1θq11\mapsto1\overline{\theta}_1\cdots\overline{\theta}_{q-1} beginning with θ0:=0\theta_0:=0, where 0:=1\overline{0}:=1 and 1:=0\overline{1}:=0. For rational functions RR, we study infinite products of the forms n=1(R(n))(1)θnandn=1(R(n))θn.\prod_{n=1}^\infty\Big(R(n)\Big)^{(-1)^{\theta_n}}\quad\text{and}\quad\prod_{n=1}^\infty\Big(R(n)\Big)^{\theta_n}. This generalizes relevant results given by Allouche, Riasat and Shallit in 2019 on infinite products related to the famous Thue-Morse sequence (tn)n0(t_n)_{n\ge0} of the forms n=1(R(n))(1)tnandn=1(R(n))tn.\prod_{n=1}^\infty\Big(R(n)\Big)^{(-1)^{t_n}}\quad\text{and}\quad\prod_{n=1}^\infty\Big(R(n)\Big)^{t_n}.

Keywords

Cite

@article{arxiv.2006.04187,
  title  = {Infinite products related to generalized Thue-Morse sequences},
  author = {Yao-Qiang Li},
  journal= {arXiv preprint arXiv:2006.04187},
  year   = {2020}
}