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2025/106/3-4 (2) — DOI: 10.5486/PMD.2025.9771 — pp. 285-299

On the explicit Galois group of $\mathbb{Q}\Big(a_{1}^{\frac{1}{m}},a_{2}^{\frac{1}{m}},\dots,a_{n}^{\frac{1}{m}},\zeta_{m}\Big)$ over $\mathbb{Q}$

Authors: Chinnakonda Gnanamoorthy Karthick Babu Orcid.org link for Chinnakonda Gnanamoorthy Karthick Babu, Prem Prakash Pandey Orcid.org link for  Prem Prakash Pandey and Mahesh Kumar Ram Orcid.org link for Mahesh Kumar Ram

Abstract:

Let $m>1$ be an integer, and $\zeta_m$ denote a primitive $m$-th root of unity. For any finite set $S= \{ a_{1}, a_{2}, \dots, a_{n} \}$ and arbitrary choice of $m$-th roots of unity $\zeta_m^{r_i}$, $0 \leq r_i < m$ for $i=1, \dots, n$, we study the density of primes $\mathbf{p}$ of $\mathbb{Q}(\zeta_m)$ such that the $m$-th power residue symbol $\left(\frac{a_i}{\mathbf{p}}\right)_m =\zeta_m^{r_i}$. We calculate the explicit structure of the Galois group $\operatorname{Gal}{\mathbb{Q}(a_1^{\frac{1}{m}}, \ldots, a_n^{\frac{1}{m}},\zeta_m)/\mathbb{Q}(\zeta_{m})}$ in terms of its action on $a_{i}^{\frac{1}{m}}$ for $1 \leq i \leq n$.

Keywords: $m$-th power residue, extensions obtained by adjoining $m$-th roots, distribution of prime ideals

Mathematics Subject Classification: 11R21, 11R18, 11R44