Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-20T03:53:09.215Z Has data issue: false hasContentIssue false

Dynamical properties of the negative beta-transformation

Published online by Cambridge University Press:  14 October 2011

LINGMIN LIAO
Affiliation:
LAMA, CNRS UMR 8050, Université Paris-Est—Créteil—Val-de-Marne, UFR Sciences et Technologie, 61 Avenue du Général de Gaulle, 94010 Créteil Cedex, France (email: [email protected])
WOLFGANG STEINER
Affiliation:
LIAFA, CNRS UMR 7089, Université Paris Diderot – Paris 7, Case 7014, 75205 Paris Cedex 13, France (email: [email protected])

Abstract

We analyse dynamical properties of the negative beta-transformation, which has been studied recently by Ito and Sadahiro. Contrary to the classical beta-transformation, the density of the absolutely continuous invariant measure of the negative beta-transformation may be zero on certain intervals. By investigating this property in detail, we prove that the (−β)-transformation is exact for all β>1, confirming a conjecture of Góra, and intrinsic, which completes a study of Faller. We also show that the limit behaviour of the (−β)-expansion of 1 when β tends to 1 is related to the Thue–Morse sequence. A consequence of the exactness is that every Yrrap number, which is a β>1 such that the (−β) -expansion of 1 is eventually periodic, is a Perron number. This extends a well-known property of Parry numbers. However, the set of Parry numbers is different from the set of Yrrap numbers.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1]Allouche, J.-P., Arnold, A., Berstel, J., Brlek, S., Jockusch, W., Plouffe, S. and Sagan, B. E.. A relative of the Thue–Morse sequence. Discrete Math. 139(1–3) (1995), 455461.CrossRefGoogle Scholar
[2]Bertrand, A.. Développements en base de Pisot et répartition modulo 1. C. R. Acad. Sci. Paris Sér. A 285(6) (1977), 419421.Google Scholar
[3]Dubickas, A.. On the distance from a rational power to the nearest integer. J. Number Theory 117(1) (2006), 222239.CrossRefGoogle Scholar
[4]Dubickas, A.. On a sequence related to that of Thue–Morse and its applications. Discrete Math. 307(9–10) (2007), 10821093.CrossRefGoogle Scholar
[5]Faller, B.. Contribution to the ergodic theory of piecewise monotone continuous maps. PhD Thesis, École Polytechnique Fédérale de Lausanne, 2008.Google Scholar
[6]Frougny, C. and Lai, A. C.. On negative bases. Proceedings of DLT 09 (Lecture Notes in Computer Science, 5583). Springer, Berlin, 2009, pp. 252263.Google Scholar
[7]Góra, P.. Invariant densities for generalized β-maps. Ergod. Th. & Dynam. Sys. 27(5) (2007), 15831598.CrossRefGoogle Scholar
[8]Hofbauer, F.. A two parameter family of piecewise linear transformations with negative slope. Acta Math. Univ. Comenian. (N.S.) to appear.Google Scholar
[9]Hofbauer, F.. On intrinsic ergodicity of piecewise monotonic transformations with positive entropy. Israel J. Math. 34(3) (1979), 213237.CrossRefGoogle Scholar
[10]Hofbauer, F.. On intrinsic ergodicity of piecewise monotonic transformations with positive entropy. II. Israel J. Math. 38(1–2) (1981), 107115.CrossRefGoogle Scholar
[11]Hofbauer, F.. The structure of piecewise monotonic transformations. Ergod. Th. & Dynam. Sys. 1(2) (1981), 159178.CrossRefGoogle Scholar
[12]Ito, S. and Sadahiro, T.. Beta-expansions with negative bases. Integers 9(A22) (2009), 239259.CrossRefGoogle Scholar
[13]Keller, G.. Piecewise monotonic transformations and exactness. Seminar on Probability (Rennes, 1978). Université de Rennes, Rennes, 1978, Exp. No. 6, p. 32 (in French).Google Scholar
[14]Li, T.-Y. and Yorke, J. A.. Ergodic transformations from an interval into itself. Trans. Amer. Math. Soc. 235 (1978), 183192.CrossRefGoogle Scholar
[15]Lothaire, M.. Combinatorics on words. Cambridge Mathematical Library. Cambridge University Press, Cambridge, 1997.Google Scholar
[16]Masáková, Z. and Pelantová, E.. Ito–Sadahiro numbers vs. Parry numbers, arXiv:1010.6181v1 [math.NT].Google Scholar
[17]Parry, W.. On the β-expansions of real numbers. Acta Math. Acad. Sci. Hungar. 11 (1960), 401416.CrossRefGoogle Scholar
[18]Pollicott, M. and Yuri, M.. Dynamical Systems and Ergodic Theory (London Mathematical Society Student Texts, 40). Cambridge University Press, Cambridge, 1998.CrossRefGoogle Scholar
[19]Rényi, A.. Representations for real numbers and their ergodic properties. Acta Math. Acad. Sci. Hungar. 8 (1957), 477493.CrossRefGoogle Scholar
[20]Rohlin, V. A.. Exact endomorphisms of a Lebesgue space. Izv. Akad. Nauk SSSR Ser. Mat. 25 (1961), 499530.Google Scholar
[21]Schmidt, K.. On periodic expansions of Pisot numbers and Salem numbers. Bull. Lond. Math. Soc. 12(4) (1980), 269278.CrossRefGoogle Scholar
[22]Wagner, G.. The ergodic behaviour of piecewise monotonic transformations. Z. Wahrsch. Verw. Gebiete 46(3) (1979), 317324.CrossRefGoogle Scholar
[23]Walters, P.. Invariant measures and equilibrium states for some mappings which expand distances. Trans. Amer. Math. Soc. 236 (1978), 121153.CrossRefGoogle Scholar