The McKay conjecture with group automorphisms and the Okuyama-Wajima argument

Fuente: arXiv
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Main Authors: Maltempo, Adele, Vallejo, Carolina
Format: Preprint
Published: 2025
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author Maltempo, Adele
Vallejo, Carolina
author_facet Maltempo, Adele
Vallejo, Carolina
contents Let $N$ be normal subgroup of a finite group $G$, $p$ be a prime, $P$ be a Sylow $p$-subgroup of $G$ and $θ$ be a $P$-invariant irreducible character of $N$. Suppose that $G/N$ is a $p$-solvable group. In this note we show that, whenever a finite group $A$ acts on $G$ stabilizing $P$, there exists an $A$-equivariant McKay bijection between irreducible characters lying over $θ$ of degree prime to $p$ of $G$ and $\textbf{N}_G(P)$. This is a consequence of a recent result of D. Rossi. Our approach here is independent from Rossi's and follows the original idea of the proof of the McKay conjecture for $p$-solvable groups. In particular, we rely on the so-called Okuyama-Wajima argument to deal with characters above Glauberman correspondents. For this purpose, we generalize a classical result of P. X. Gallagher on the number of irreducible characters of $G$ lying over $θ$.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13406
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The McKay conjecture with group automorphisms and the Okuyama-Wajima argument
Maltempo, Adele
Vallejo, Carolina
Representation Theory
Group Theory
20C15
Let $N$ be normal subgroup of a finite group $G$, $p$ be a prime, $P$ be a Sylow $p$-subgroup of $G$ and $θ$ be a $P$-invariant irreducible character of $N$. Suppose that $G/N$ is a $p$-solvable group. In this note we show that, whenever a finite group $A$ acts on $G$ stabilizing $P$, there exists an $A$-equivariant McKay bijection between irreducible characters lying over $θ$ of degree prime to $p$ of $G$ and $\textbf{N}_G(P)$. This is a consequence of a recent result of D. Rossi. Our approach here is independent from Rossi's and follows the original idea of the proof of the McKay conjecture for $p$-solvable groups. In particular, we rely on the so-called Okuyama-Wajima argument to deal with characters above Glauberman correspondents. For this purpose, we generalize a classical result of P. X. Gallagher on the number of irreducible characters of $G$ lying over $θ$.
title The McKay conjecture with group automorphisms and the Okuyama-Wajima argument
topic Representation Theory
Group Theory
20C15
url https://arxiv.org/abs/2512.13406