English

Irrationality and transcendence questions in the "poor man's ad\`ele ring"

Number Theory 2025-06-26 v2

Abstract

We discuss arithmetic questions related to the "poor man's ad\`ele ring" A\mathcal A whose elements are encoded by sequences (tp)p(t_p)_p indexed by prime numbers, with each tpt_p viewed as a residue in Z/pZ\mathbb Z/p\mathbb Z. Our main theorem is about the A\mathcal A-transcendence of the element (Fp(q))p(F_p(q))_p, where Fn(q)F_n(q) (Schur's qq-Fibonacci numbers) are the (1,1)(1,1)-entries of 2×22\times2-matrices (1110)(11q0)(11q20)(11qn20) \bigg(\begin{matrix} 1 & 1 \\ 1 & 0 \end{matrix}\bigg) \bigg(\begin{matrix} 1 & 1 \\ q & 0 \end{matrix}\bigg) \bigg(\begin{matrix} 1 & 1 \\ q^2 & 0 \end{matrix}\bigg) \cdots \bigg(\begin{matrix} 1 & 1 \\ q^{n-2} & 0 \end{matrix}\bigg) and q>1q>1 is an integer. This result was previously known for q>1q>1 square free under the GRH.

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Cite

@article{arxiv.2505.09775,
  title  = {Irrationality and transcendence questions in the "poor man's ad\`ele ring"},
  author = {Florian Luca and Wadim Zudilin},
  journal= {arXiv preprint arXiv:2505.09775},
  year   = {2025}
}

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7 pages