English

Bijective and general arithmetic codings for Pisot automorphisms of the torus

Dynamical Systems 2007-05-23 v1 Number Theory

Abstract

Let TT be an algebraic automorphism of Tm\mathbb{T}^{m} having the following property: the characteristic polynomial of its matrix is irreducible over Q\mathbb{Q}, and a Pisot number β\beta is one of its roots. We define the mapping ϕt\phi_{\mathbf{t}} acting from the two-sided β\beta-compactum onto Tm\mathbb{T}^{m} as follows: ϕt(ϵˉ)=kZϵkTkt, \phi_{\mathbf{t}}(\bar{\epsilon})= \sum_{k\in\mathbb{Z}}\epsilon_{k}T^{-k}\mathbf{t}, where t\mathbf{t} is a fundamental homoclinic point for TT, i.e., a point homoclinic to 0\mathbf{0} such that the linear span of its orbit is the whole homoclinic group (provided such a point exists). We call such a mapping an arithmetic coding of TT. This paper is aimed to show that under some natural hypothesis on β\beta (which is apparently satisfied for all Pisot units) the mapping ϕt\phi_{\mathbf{t}} is bijective a.e. with respect to the Haar measure on the torus. Besides, we study the case of more general parameters t\mathbf{t}, not necessarily fundamental, and relate the number of preimages of ϕt\phi_{\mathbf{t}} to certain number-theoretic quantities. We also give several full criteria for TT to admit a bijective arithmetic coding. This work continues the study begun in [Sidorov & Vershik, Journal Dynam. Control Systems 4 (1998), 365-399] for the special case m=2m=2.

Keywords

Cite

@article{arxiv.math/0006159,
  title  = {Bijective and general arithmetic codings for Pisot automorphisms of the torus},
  author = {Nikita Sidorov},
  journal= {arXiv preprint arXiv:math/0006159},
  year   = {2007}
}

Comments

25 pages, Latex

R2 v1 2026-07-22T16:33:19.295Z