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Hlavní autoři: Beltrán, Antonio, Felipe, María José, Melchor, Carmen
Médium: Preprint
Vydáno: 2024
Témata:
On-line přístup:https://arxiv.org/abs/2402.06708
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author Beltrán, Antonio
Felipe, María José
Melchor, Carmen
author_facet Beltrán, Antonio
Felipe, María José
Melchor, Carmen
contents Landau's theorem on conjugacy classes asserts that there are only finitely many finite groups, up to isomorphism, with exactly $k$ conjugacy classes for any positive integer $k$. We show that, for any positive integers $n$ and $s$, there exists only a finite number of finite groups $G$, up to isomorphism, having a normal subgroup $N$ of index $n$ which contains exactly $s$ non-central $G$-conjugacy classes. We provide upper bounds for the orders of $G$ and $N$, which are used by using GAP to classify all finite groups with normal subgroups having a small index and few $G$-classes. We also study the corresponding problems when we only take into account the set of $G$-classes of prime-power order elements contained in a normal subgroup.
format Preprint
id arxiv_https___arxiv_org_abs_2402_06708
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Landau's Theorem on conjugacy classes for normal subgroups
Beltrán, Antonio
Felipe, María José
Melchor, Carmen
Group Theory
Landau's theorem on conjugacy classes asserts that there are only finitely many finite groups, up to isomorphism, with exactly $k$ conjugacy classes for any positive integer $k$. We show that, for any positive integers $n$ and $s$, there exists only a finite number of finite groups $G$, up to isomorphism, having a normal subgroup $N$ of index $n$ which contains exactly $s$ non-central $G$-conjugacy classes. We provide upper bounds for the orders of $G$ and $N$, which are used by using GAP to classify all finite groups with normal subgroups having a small index and few $G$-classes. We also study the corresponding problems when we only take into account the set of $G$-classes of prime-power order elements contained in a normal subgroup.
title Landau's Theorem on conjugacy classes for normal subgroups
topic Group Theory
url https://arxiv.org/abs/2402.06708