RUS  ENG
Full version
JOURNALS // Moscow Mathematical Journal // Archive

Mosc. Math. J., 2021 Volume 21, Number 4, Pages 767–788 (Mi mmj812)

$\mathbb{M}\backslash \mathbb{L}$ near $3$

Davi Limaa, Carlos Matheusb, Carlos Gustavo Moreirac, Sandoel Vieirac

a Instituto de Matemática, UFAL, Av. Lourival Melo Mota s/n, Maceio, Alagoas, Brazil
b CMLS, École Polytechnique, CNRS (UMR 7640), 91128, Palaiseau, France
c IMPA, Estrada Dona Castorina, 110. Rio de Janeiro, Rio de Janeiro-Brazil

Abstract: We construct four new elements $3.11>m_1>m_2>m_3>m_4$ of $\mathbb{M}\backslash \mathbb{L}$ lying in distinct connected components of $\mathbb{R}\setminus \mathbb{L}$, where $\mathbb{M}$ is the Markov spectrum and $\mathbb{L}$ is the Lagrange spectrum. These elements are part of a decreasing sequence $(m_k)_{k\in\mathbb{N}}$ of elements in $\mathbb{M}$ converging to $3$ and we give some evidence towards the possibility that $m_k\in \mathbb{M}\setminus \mathbb{L}$ for all $k\geq 1$. In particular, this indicates that $3$ might belong to the closure of $\mathbb{M}\setminus \mathbb{L}$. So, $\mathbb{M}\setminus \mathbb{L}$ would not be closed near $3$ and there would not exist $\varepsilon>0$ such that $\mathbb{M}\cap (-\infty,3+\varepsilon)=\mathbb{L}\cap (-\infty,3+\varepsilon).$

Key words and phrases: Markov spectrum, Lagrange spectrum, Diophantine approximation.

MSC: 11A55, 11J06

Language: English

DOI: 10.17323/1609-4514-2021-21-4-767-766



© Steklov Math. Inst. of RAS, 2025