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arXiv 2109.02130math.NT
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代数扩张上整矩阵的共轭性

Conjugacy of Integral Matrices over Algebraic Extensions

Rebecca Afandi

摘要:

本文研究了具有子环$\mathbb{Z}$的环$R$的整矩阵与$\text{GL}_{n}(R)$中元素的共轭性.我们注意到,哈塞原理在矩阵共轭的上下文中不成立,因为对于所有$p$都是$\text{GL}_{n}(\mathbb{Z}_p)$ -共轭的矩阵不一定是$\text{GL}_{n}(\mathbb{Z})$ -共轭的。通过Guralnick定理,我们知道整数$n \times n$矩阵对所有素数$p$是$\text{GL}_{n}(\mathbb{Z}_p)$ -共轭的当且仅当它们被$\mathbb{Z}$的某个代数整数扩张$E$的$\text{GL}_{n}(E)$中的元素共轭.我们研究的问题,找到这个扩展$E$。由于Latimer和MacDuffee关于描述$\mathbb{Z}$ -共轭性的一个结果可以推广到$R$ -共轭性的上下文中,对于$R$的任何整环,我们可以将现有的$\mathbb{Z}$ -共轭性的算法应用到新的上下文中。我们还提供了一种方法来寻找$E$,它利用类域理论的主要理想定理。我们用几个例子来说明我们的方法。

英文摘要:

We consider conjugacy of integral matrices by elements in $\text{GL}_{n}(R)$ for certain rings $R$ with subring $\mathbb{Z}$. We note that a Hasse principal does not hold in the context of matrix conjugacy because matrices which are $\text{GL}_{n}(\mathbb{Z}_p)$-conjugate for all $p$ are not necessarily $\text{GL}_{n}(\mathbb{Z})$-conjugate. By a theorem of Guralnick, we know that integral $n \times n$ matrices are $\text{GL}_{n}(\mathbb{Z}_p)$-conjugate for all primes $p$ if and only if they are conjugate by an element in $\text{GL}_{n}(E)$ for some algebraic integral extension $E$ of $\mathbb{Z}$. We study the problem of finding this extension $E$. Since a result by Latimer and MacDuffee for describing $\mathbb{Z}$-conjugacy can be generalized to the context of $R$-conjugacy for $R$ any integral domain, we can adapt an existing algorithm for $\mathbb{Z}$-conjugacy to a new context. We also offer a method for finding $E$ which makes use of the principal ideal theorems of class field theory. We illustrate our method in several examples.

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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