English

Algebraic approximations to linear combinations of S-units

Number Theory 2025-11-19 v3

Abstract

Let Γ\Qˉ×\Gamma\subset \bar{\Q}^{\times} be a finitely generated multiplicative group of algebraic numbers, let α1,,αm\alpha_1,\ldots,\alpha_m be non-zero algebraic numbers, and let ε>0\varepsilon >0 be fixed. In this paper, we prove that there exist only finitely many tuples (u1,,um,q,p)Γm×Z2(u_1, \ldots, u_m, q, p)\in \Gamma^m\times\mathbb{Z}^2 with d=[Q(u1,,um):Q]d = [\mathbb{Q}(u_1, \ldots, u_m):\mathbb{Q}] such that for any two tuples (u1,,um)(u_1,\ldots,u_m) and (u1,,um)(u'_1,\ldots,u'_m), we have ui1ui2ui1ui2\frac{u_{i_1}}{u_{i_2}}\neq \frac{u'_{i_1}}{u'_{i_2}} for 1i1i2m1\leq i_1\neq i_2\leq m and it is stable under Galois conjugation over \Q\Q, max{α1qu1,,αmqum}>1\max\{|\alpha_1 qu_1|, \ldots, |\alpha_m qu_m|\}>1, the tuple (α1qu1,,αmqum)(\alpha_1qu_1, \ldots, \alpha_mq u_m) is not pseudo-Pisot and 0<i=1mαiquip<1(i=1mH(ui))εqmd+ε,0< \left|\sum_{i=1}^m \alpha_iq u_i - p\right|<\frac{1}{\left(\prod_{i=1}^mH( u_i)\right)^{\varepsilon} |q|^{md+\varepsilon}}, where H(ui)H(u_i) denotes the absolute Weil height. This result extends one of the main results of Corvaja-Zannier \cite{corv}. In addition, we prove a result similar to \cite[Theorem 1.4]{kul} in a more general setting. In our proofs, we exploit the subspace theorem based on the work of Corvaja-Zannier.

Keywords

Cite

@article{arxiv.2506.02898,
  title  = {Algebraic approximations to linear combinations of S-units},
  author = {Parvathi S Nair and Veekesh Kumar and S. S. Rout},
  journal= {arXiv preprint arXiv:2506.02898},
  year   = {2025}
}
R2 v1 2026-07-01T02:57:00.426Z