English

Counting Exceptional Points for Rational Numbers Associated to the Fibonacci Sequence

Number Theory 2019-12-23 v1

Abstract

If α\alpha is a non-zero algebraic number, we let m(α)m(\alpha) denote the Mahler measure of the minimal polynomial of α\alpha over Z\mathbb Z. A series of articles by Dubickas and Smyth, and later by the author, develop a modified version of the Mahler measure called the tt-metric Mahler measure, denoted mt(α)m_t(\alpha). For fixed αQˉ\alpha\in \bar{\mathbb Q}, the map tmt(α)t\mapsto m_t(\alpha) is continuous, and moreover, is infinitely differentiable at all but finitely many points, called {\it exceptional points} for α\alpha. It remains open to determine whether there is a sequence of elements αnQˉ\alpha_n\in \bar{\mathbb Q} such that the number of exceptional points for αn\alpha_n tends to \infty as nn\to \infty. We utilize a connection with the Fibonacci sequence to formulate a conjecture on the tt-metric Mahler measures. If the conjecture is true, we prove that it is best possible and that it implies the the existence of rational numbers with as many exceptional points as we like. Finally, with some computational assistance, we resolve various special cases of the conjecture that constitute improvements to earlier results.

Keywords

Cite

@article{arxiv.1607.02081,
  title  = {Counting Exceptional Points for Rational Numbers Associated to the Fibonacci Sequence},
  author = {Charles L. Samuels},
  journal= {arXiv preprint arXiv:1607.02081},
  year   = {2019}
}
R2 v1 2026-06-22T14:48:26.486Z