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On the reciprocity law in $\mathbb{F}_{q}[t]$

Number Theory 2026-04-24 v1

Abstract

In 1991, Rousseau gave a new proof of Gauss's quadratic reciprocity by comparing two distinct coset representations of the group (Zp×Zq)/U(\mathbb{Z}_{p}^{*} \times \mathbb{Z}_{q}^{*}) / U using the Chinese Remainder Theorem, without Gauss's Lemma. In this paper, we extend Rousseau's approach to Fq[t]\mathbb{F}_{q}[t], providing a new, elementary proof of the reciprocity law for the ddth power residue symbol, where dd is any divisor of q1q-1.

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Cite

@article{arxiv.2604.20892,
  title  = {On the reciprocity law in $\mathbb{F}_{q}[t]$},
  author = {Su Hu and Enci Wang},
  journal= {arXiv preprint arXiv:2604.20892},
  year   = {2026}
}

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4 pages