Hostname: page-component-6bf8c574d5-2jptb Total loading time: 0 Render date: 2025-02-21T05:36:47.650Z Has data issue: false hasContentIssue false

A canonical thickening of ℚ and the entropy of α-continued fraction transformations

Published online by Cambridge University Press:  14 September 2011

CARLO CARMINATI
Affiliation:
Dipartimento di Matematica, Università di Pisa, Largo Bruno Pontecorvo 5, 56127 Pisa, Italy (email: carminat@dm.unipi.it)
GIULIO TIOZZO
Affiliation:
Department of Mathematics, Harvard University, 1 Oxford Street, 02138 Cambridge, MA, USA (email: tiozzo@math.harvard.edu)
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We construct a countable family of open intervals contained in (0,1] whose endpoints are quadratic surds and such that their union is a full measure set. We then show that these intervals are precisely the monotonicity intervals of the entropy of α-continued fractions, thus proving a conjecture of Nakada and Natsui.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2011

References

[BDV02]Bourdon, J., Daireaux, B. and Vallée, B.. Dynamical analysis of α-Euclidean algorithms. J. Algorithms 44(1) (2002), 246285.CrossRefGoogle Scholar
[CMPT10]Carminati, C., Marmi, S., Profeti, A. and Tiozzo, G.. The entropy of α-continued fractions: numerical results. Nonlinearity 23 (2010), 24292456.CrossRefGoogle Scholar
[Cas95]Cassa, A.. Dinamiche caotiche e misure invarianti, Tesi di Laurea, Facoltà di Scienze Matematiche, Fisiche e Naturali, University of Florence, 1995.Google Scholar
[CMM99]Cassa, A., Moussa, P. and Marmi, S.. Continued fractions and Brjuno functions. J. Comput. Appl. Math. 105(1–2) (1999), 403415.Google Scholar
[GS96]Graczyk, J. and Świa̧tek, G.. Critical circle maps near bifurcation. Comm. Math. Phys. 176 (1996), 227260.CrossRefGoogle Scholar
[Jar28]Jarník, V.. Zur metrischen Theorie der diophantische Approximationen. Prace Mat.-Fiz. 36(1928–9), 91106.Google Scholar
[KU10]Katok, S. and Ugarcovici, I.. Structure of attractors for (a,b)-continued fraction transformations. J. Mod. Dyn. 4(4) (2010), 637691.CrossRefGoogle Scholar
[LM08]Luzzi, L. and Marmi, S.. On the entropy of Japanese continued fractions. Discrete Contin. Dyn. Syst. 20 (2008), 673711.CrossRefGoogle Scholar
[Nak81]Nakada, H.. Metrical theory for a class of continued fraction transformations and their natural extensions. Tokyo J. Math. 4 (1981), 399426.CrossRefGoogle Scholar
[NN08]Nakada, H. and Natsui, R.. The non-monotonicity of the entropy of α-continued fraction transformations. Nonlinearity 21 (2008), 12071225.CrossRefGoogle Scholar
[Sch05]Schuster, H. G. and Jost, W.. Deterministic Chaos: An Introduction, 4th edn. Wiley-VCH, Weinheim, Germany, 2005.CrossRefGoogle Scholar