English

$p$-Adic quotient sets: linear recurrence sequences with reducible characteristic polynomials

Number Theory 2024-08-14 v1

Abstract

Let (xn)n0(x_n)_{n\geq0} be a linear recurrence sequence of order k2k\geq2 satisfying xn=a1xn1+a2xn2++akxnkx_n=a_1x_{n-1}+a_2x_{n-2}+\dots+a_kx_{n-k} for all integers nkn\geq k, where a1,,ak,x0,,xk1Z,a_1,\dots,a_k,x_0,\dots, x_{k-1}\in \mathbb{Z}, with ak0a_k\neq0. In 2017, Sanna posed an open question to classify primes pp for which the quotient set of (xn)n0(x_n)_{n\geq0} is dense in Qp\mathbb{Q}_p. In a recent paper, we showed that if the characteristic polynomial of the recurrence sequence has a root ±α\pm \alpha, where α\alpha is a Pisot number and if pp is a prime such that the characteristic polynomial of the recurrence sequence is irreducible in Qp\mathbb{Q}_p, then the quotient set of (xn)n0(x_n)_{n\geq 0} is dense in Qp\mathbb{Q}_p. In this article, we answer the problem for certain linear recurrence sequences whose characteristic polynomials are reducible over Q\mathbb{Q}.

Keywords

Cite

@article{arxiv.2408.06949,
  title  = {$p$-Adic quotient sets: linear recurrence sequences with reducible characteristic polynomials},
  author = {Deepa Antony and Rupam Barman},
  journal= {arXiv preprint arXiv:2408.06949},
  year   = {2024}
}

Comments

To appear at Canadian Mathematical Bulletin. arXiv admin note: text overlap with arXiv:2207.07084

R2 v1 2026-06-28T18:11:50.692Z