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JOURNALS // Algebra and Discrete Mathematics // Archive

Algebra Discrete Math., 2009 Issue 2, Pages 99–107 (Mi adm122)

This article is cited in 2 papers

RESEARCH ARTICLE

On Galois groups of prime degree polynomials with complex roots

Oz Ben-Shimol

Department of Mathematics, University of Haifa, Mount Carmel  1905, Haifa, Israel

Abstract: Let $f$ be an irreducible polynomial of prime degree $p\geq 5$ over $\mathbb{Q}$, with precisely $k$ pairs of complex roots. Using a result of Jens Höchsmann (1999), we show that if $p\geq 4k+1$ then $\rm{Gal}(f/\mathbb{Q})$ is isomorphic to $A_{p}$ or $S_{p}$. This improves the algorithm for computing the Galois group of an irreducible polynomial of prime degree, introduced by A. Bialostocki and T. Shaska.
If such a polynomial $f$ is solvable by radicals then its Galois group is a Frobenius group of degree p. Conversely, any Frobenius group of degree p and of even order, can be realized as the Galois group of an irreducible polynomial of degree $p$ over $\mathbb{Q}$ having complex roots.

MSC: 20B35, 12F12

Received: 06.09.2008
Revised: 15.04.2009

Language: English



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