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arXiv · 2210.10257

Galois groups of certain even octic polynomials

Malcolm Hoong Wai Chen·Angelina Yan Mui Chin·Ta Sheng Tan
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Abstract

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 $x^8+ax^6+bx^4+ax^2+1 \in \mathbb{Q}[x]$.

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BibTeXRIS

Malcolm Hoong Wai Chen, Angelina Yan Mui Chin, Ta Sheng Tan. 2022-10-19. Galois groups of certain even octic polynomials. https://doi.org/10.1142/s0219498823502638

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