English

On simultaneous approximation of algebraic numbers

Number Theory 2022-10-04 v3

Abstract

Let ΓQˉ×\Gamma\subset \bar{\mathbb Q}^{\times} be a finitely generated multiplicative group of algebraic numbers. Let α1,,αrQˉ×\alpha_1,\ldots,\alpha_r\in\bar{\mathbb Q}^\times be algebraic numbers which are Q\mathbb{Q}-linearly independent and let ϵ>0\epsilon>0 be a given real number. One of the main results that we prove in this article is as follows; There exist only finitely many tuples (u,q,p1,,pr)Γ×Zr+1(u, q, p_1,\ldots,p_r)\in\Gamma\times\mathbb{Z}^{r+1} with d=[Q(u):Q]d = [\mathbb{Q}(u):\mathbb{Q}] for some integer d1d\geq 1 satisfying αiqu>1|\alpha_i q u|>1, αiqu\alpha_i q u is not a pseudo-Pisot number for some integer i{1,,r}i\in\{1, \ldots, r\} and 0<αjqupj<1Hϵ(u)qdr+ε 0<|\alpha_j qu-p_j|<\frac{1}{H^\epsilon(u)|q|^{\frac{d}{r}+\varepsilon}} for all integers j=1,2,,rj = 1, 2,\ldots, r, where H(u)H(u) is the absolute Weil height. In particular, when r=1r =1, this result was proved by Corvaja and Zannier in [3]. As an application of our result, we also prove a transcendence criterion which generalizes a result of Han\v{c}l, Kolouch, Pulcerov\'a and \v{S}t\v{e}pni\v{c}ka in [4]. The proofs rely on the clever use of the subspace theorem and the underlying ideas from the work of Corvaja and Zannier.

Keywords

Cite

@article{arxiv.2001.00386,
  title  = {On simultaneous approximation of algebraic numbers},
  author = {Veekesh Kumar and R. Thangadurai},
  journal= {arXiv preprint arXiv:2001.00386},
  year   = {2022}
}

Comments

Accepted for publication in 'Mathematika'

R2 v1 2026-06-23T13:01:15.132Z