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arXiv 2007.14183math.NTmath.AC
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切比雪夫多项式与De Moivre多项式的伽罗瓦群

Chebyshev polynomials and Galois groups of De Moivre polynomials

Kurt Girstmair

摘要:

设$n\ge 3$为奇数自然数。在1738年,亚伯拉罕·德·莫夫尔引入了一系列具有有理系数的$n$次多项式,所有这些多项式都是可解的。到目前为止,这些多项式的伽罗瓦群只研究了素数$n$和特殊假设。我们描述的伽罗瓦群的任意奇数$n\ge 3$在不可约的情况下,到少数例外。此外,我们还将这样一个多项式的所有零点表示为三个零点的有理函数,其中两个零点在某种意义上是连通的。这些结果是基于自由基$$ \sqrt[n]{d+\sqrt R}, $$的程度一般是$2n$,减少到有理数的程度$\le n$。作者在以前的一篇论文中给出了这种减少。然而,在这里,我们提出了一个更简单的方法,是基于切比雪夫多项式的属性。

英文摘要:

Let $n\ge 3$ be an odd natural number. In 1738, Abraham de Moivre introduced a family of polynomials of degree $n$ with rational coefficients, all of which are solvable. So far, the Galois groups of these polynomials have been investigated only for prime numbers $n$ and under special assumptions. We describe the Galois groups for arbitrary odd $n\ge 3$ in the irreducible case, up to few exceptions. In addition, we express all zeros of such a polynomial as rational functions of three zeros, two of which are connected in a certain sense. These results are based on the reduction of the radical $$ \sqrt[n]{d+\sqrt R}, $$ whose degree is $2n$ in general, to irrationals of degree $\le n$. Such a reduction was given in a previous paper of the author. Here, however, we present a much simpler approach that is based on properties of Chebyshev polynomials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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