Galois groups of certain even octic polynomials

Fuente: arXiv
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Main Authors: Chen, Malcolm Hoong Wai, Chin, Angelina Yan Mui, Tan, Ta Sheng
Format: Preprint
Published: 2022
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_version_ 1866912927059017728
author Chen, Malcolm Hoong Wai
Chin, Angelina Yan Mui
Tan, Ta Sheng
author_facet Chen, Malcolm Hoong Wai
Chin, Angelina Yan Mui
Tan, Ta Sheng
contents Let $f(x)=x^8+ax^4+b \in \mathbb{Q}[x]$ be an irreducible polynomial where $b$ is a square. We give a method that completely describes the factorization patterns of a linear resolvent of $f(x)$ using simple arithmetic conditions on $a$ and $b$. As a result, we determine the exact six possible Galois groups of $f(x)$ and completely classify all of them. As an application, we characterize the Galois groups of irreducible polynomials $x^8+ax^4+1 \in \mathbb{Q}[x]$. We also use similar methods to obtain analogous results for the Galois groups of irreducible polynomials $x^8+ax^6+bx^4+ax^2+1 \in \mathbb{Q}[x]$.
format Preprint
id arxiv_https___arxiv_org_abs_2210_10257
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Galois groups of certain even octic polynomials
Chen, Malcolm Hoong Wai
Chin, Angelina Yan Mui
Tan, Ta Sheng
Number Theory
12F10, 11R09, 12D05, 12-08
Let $f(x)=x^8+ax^4+b \in \mathbb{Q}[x]$ be an irreducible polynomial where $b$ is a square. We give a method that completely describes the factorization patterns of a linear resolvent of $f(x)$ using simple arithmetic conditions on $a$ and $b$. As a result, we determine the exact six possible Galois groups of $f(x)$ and completely classify all of them. As an application, we characterize the Galois groups of irreducible polynomials $x^8+ax^4+1 \in \mathbb{Q}[x]$. We also use similar methods to obtain analogous results for the Galois groups of irreducible polynomials $x^8+ax^6+bx^4+ax^2+1 \in \mathbb{Q}[x]$.
title Galois groups of certain even octic polynomials
topic Number Theory
12F10, 11R09, 12D05, 12-08
url https://arxiv.org/abs/2210.10257