On the minimal degree and base size of finite primitive groups

Fuente: arXiv
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Autore principale: Mastrogiacomo, Fabio
Natura: Preprint
Pubblicazione: 2024
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author Mastrogiacomo, Fabio
author_facet Mastrogiacomo, Fabio
contents Let $G$ be a finite permutation group acting on $Ω$. A base for $G$ is a subset $B \subseteq Ω$ such that the pointwise stabilizer $G_{(B)}$ is the identity. The base size of $G$, denoted by $b(G)$, is the cardinality of the smallest possible base. The minimal degree of $G$, denoted by $μ(G)$, is the smallest cardinality of the support of a non trivial element of $G$. In this paper, we establish a new upper bound for $b(G)$ when $G$ is primitive, and subsequently prove that if $G$ is a primitive group different from the Mathieu group of degree $24$, then $μ(G)b(G)\leq n \log n$, where $n$ is the degree of $G$. This bound is best possible, up to a multiplicative constant.
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spellingShingle On the minimal degree and base size of finite primitive groups
Mastrogiacomo, Fabio
Group Theory
Let $G$ be a finite permutation group acting on $Ω$. A base for $G$ is a subset $B \subseteq Ω$ such that the pointwise stabilizer $G_{(B)}$ is the identity. The base size of $G$, denoted by $b(G)$, is the cardinality of the smallest possible base. The minimal degree of $G$, denoted by $μ(G)$, is the smallest cardinality of the support of a non trivial element of $G$. In this paper, we establish a new upper bound for $b(G)$ when $G$ is primitive, and subsequently prove that if $G$ is a primitive group different from the Mathieu group of degree $24$, then $μ(G)b(G)\leq n \log n$, where $n$ is the degree of $G$. This bound is best possible, up to a multiplicative constant.
title On the minimal degree and base size of finite primitive groups
topic Group Theory
url https://arxiv.org/abs/2411.03469