Comments on the fractional parts of Pisot numbers

Toufik Zaïmi; Mounia Selatnia; Hanifa Zekraoui

Archivum Mathematicum (2015)

  • Volume: 051, Issue: 3, page 153-161
  • ISSN: 0044-8753

Abstract

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Let L ( θ , λ ) be the set of limit points of the fractional parts { λ θ n } , n = 0 , 1 , 2 , , where θ is a Pisot number and λ ( θ ) . Using a description of L ( θ , λ ) , due to Dubickas, we show that there is a sequence ( λ n ) n 0 of elements of ( θ ) such that Card ( L ( θ , λ n ) ) < Card ( L ( θ , λ n + 1 ) ) , n 0 . Also, we prove that the fractional parts of Pisot numbers, with a fixed degree greater than 1, are dense in the unit interval.

How to cite

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Zaïmi, Toufik, Selatnia, Mounia, and Zekraoui, Hanifa. "Comments on the fractional parts of Pisot numbers." Archivum Mathematicum 051.3 (2015): 153-161. <http://eudml.org/doc/271634>.

@article{Zaïmi2015,
abstract = {Let $L(\theta ,\lambda )$ be the set of limit points of the fractional parts $\lbrace \lambda \theta ^\{n\}\rbrace $, $n=0,1,2, \dots $, where $\theta $ is a Pisot number and $\lambda \in \mathbb \{Q\}(\theta )$. Using a description of $L(\theta ,\lambda )$, due to Dubickas, we show that there is a sequence $(\lambda _\{n\})_\{n\ge 0\}$ of elements of $\mathbb \{Q\}(\theta )$ such that $\operatorname\{Card\}\,(L(\theta ,\lambda _\{n\}))< \operatorname\{Card\}\,(L(\theta ,\lambda _\{n+1\}))$, $\forall $$n\ge 0$. Also, we prove that the fractional parts of Pisot numbers, with a fixed degree greater than 1, are dense in the unit interval.},
author = {Zaïmi, Toufik, Selatnia, Mounia, Zekraoui, Hanifa},
journal = {Archivum Mathematicum},
keywords = {Pisot numbers; fractional parts; limit points},
language = {eng},
number = {3},
pages = {153-161},
publisher = {Department of Mathematics, Faculty of Science of Masaryk University, Brno},
title = {Comments on the fractional parts of Pisot numbers},
url = {http://eudml.org/doc/271634},
volume = {051},
year = {2015},
}

TY - JOUR
AU - Zaïmi, Toufik
AU - Selatnia, Mounia
AU - Zekraoui, Hanifa
TI - Comments on the fractional parts of Pisot numbers
JO - Archivum Mathematicum
PY - 2015
PB - Department of Mathematics, Faculty of Science of Masaryk University, Brno
VL - 051
IS - 3
SP - 153
EP - 161
AB - Let $L(\theta ,\lambda )$ be the set of limit points of the fractional parts $\lbrace \lambda \theta ^{n}\rbrace $, $n=0,1,2, \dots $, where $\theta $ is a Pisot number and $\lambda \in \mathbb {Q}(\theta )$. Using a description of $L(\theta ,\lambda )$, due to Dubickas, we show that there is a sequence $(\lambda _{n})_{n\ge 0}$ of elements of $\mathbb {Q}(\theta )$ such that $\operatorname{Card}\,(L(\theta ,\lambda _{n}))< \operatorname{Card}\,(L(\theta ,\lambda _{n+1}))$, $\forall $$n\ge 0$. Also, we prove that the fractional parts of Pisot numbers, with a fixed degree greater than 1, are dense in the unit interval.
LA - eng
KW - Pisot numbers; fractional parts; limit points
UR - http://eudml.org/doc/271634
ER -

References

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  1. Bertin, M.J., Decomps-Guilloux, A., Grandet-Hugo, M., Pathiaux-Delefosse, M., Schreiber, J.P., Pisot and Salem numbers, Birkhäuser Verlag Basel, 1992. (1992) MR1187044
  2. Boyd, D.W., Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory, Proc. of the 1991 CNTA Conference, Oxford University Press, 1993, pp. 333–340. (1993) Zbl0790.11012MR1368431
  3. Bugeaud, Y., An introduction to diophantine approximation, Cambridge University Press, Cambridge, 2012. (2012) MR2953186
  4. Dubickas, A., On the limit points of the fractional parts of powers of Pisot numbers, Arch. Math. (Brno) 42 (2006), 151–158. (2006) Zbl1164.11026MR2240352
  5. Marcus, D., Number fields, Springer, Berlin, 1977, 3rd edition. (1977) Zbl0383.12001MR0457396
  6. Smyth, C.J., The conjugates of algebraic integers, Amer. Math. Monthly 82 (86) (1975). (1975) 
  7. Zaïmi, T., 10.5486/PMD.2012.5098, Publ. Math. Debrecen 80 (2012), 417–426. (2012) Zbl1263.11067MR2943014DOI10.5486/PMD.2012.5098
  8. Zaïmi, T., 10.1017/S0017089511000462, Glasgow Math. J. 54 (2012), 127–132. (2012) Zbl1303.11118MR2862390DOI10.1017/S0017089511000462

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