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We classify the finite groups $G$ which satisfies the condition that every complex irreducible character,whose degree's square doesn't divide the index of its kernel in $G$, lies in the same Galois conjugacy class.

Group Theory · Mathematics 2022-08-17 Yu Zeng , Dongfang Yang

Let $q$ be a power of a prime $p$ and let $U(q)$ be a Sylow $p$-subgroup of a finite Chevalley group $G(q)$ defined over the field with $q$ elements. We first give a parametrization of the set $\text{Irr}(U(q))$ of irreducible characters of…

Representation Theory · Mathematics 2017-08-21 Tung Le , Kay Magaard , Alessandro Paolini

Given a finite group $G$ and an irreducible complex character $\chi$ of $G$, the codegree of $\chi$ is defined as the integer ${\rm cod}(\chi)=|G:\ker\chi|/\chi(1)$. It was conjectured by G. Qian in [13] that, for every element $g$ of $G$,…

Group Theory · Mathematics 2023-06-16 Z. Akhlaghi , E. Pacifici , L. Sanus

A classical theorem on character degrees states that if a finite group has fewer than four character degrees, then the group is solvable. We prove a corresponding result on character values by showing that if a finite group has fewer than…

Group Theory · Mathematics 2021-06-30 Sesuai Y. Madanha

The codegree of an irreducible character $\chi$ of a finite group $G$ is defined as $|G:\ker\chi|/\chi(1)$. The codegree graph $\Gamma(G)$ of a finite group $G$ is the graph whose vertices are the prime divisors of $|G|$, where two distinct…

Group Theory · Mathematics 2025-10-20 Jiyong Chen , Ni Du , Leyi Li

For a finite group $G$, let $\Delta(G)$ denote the character graph built on the set of degrees of the irreducible complex characters of $G$. In this paper, we show that if the diameter of $\Delta(G)$ is equal to three, then the complement…

Group Theory · Mathematics 2019-09-10 Mahdi Ebrahimi

For an irreducible complex character \(\chi\) of a finite group \(G\), the \emph{codegree} of \(\chi\) is defined as the ratio \(|G : \ker(\chi)| / \chi(1)\), where \(\ker(\chi)\) represents the kernel of \(\chi\). In this paper, we provide…

Group Theory · Mathematics 2025-10-10 Yu Zeng , Mehdi Ghaffarzadeh , Mohsen Ghasemi , Dongfang Yang

Let G be a finite group of order n and V an irreducible representation over the complex numbers of dimension d. For some nonnegative number e, we have n=d(d+e). If e is small, then the character of V has unusually large degree. We fix e and…

Group Theory · Mathematics 2008-08-28 Noah Snyder

We classify the finite groups whose non-linear irreducible characters that are not conjugate under the natural Galois action have distinct degrees, therefore extending the results in Berkovich et al. [Proc. Amer. Math. Soc. {\bf 115}…

Group Theory · Mathematics 2016-03-11 Silvio Dolfi , Manoj K. Yadav

we obtain a necessary condition for the character degree graph with all of its vertices are odd degree of a finite solvable group G.

Group Theory · Mathematics 2023-05-23 G. Sivanesan , C. Selvaraj

Let $G$ be a finite group, and let ${\rm{cd}}(G)$ denote the set of degrees of the irreducible complex characters of $G$. Define then the character degree graph $\Delta(G)$ as the (simple undirected) graph whose vertices are the prime…

Group Theory · Mathematics 2022-09-16 Silvio Dolfi , Emanuele Pacifici , Lucia Sanus

Let $G$ be a finite group. Denoting by ${\rm{cd}}(G)$ the set of the degrees of the irreducible complex characters of $G$, we consider the {\it character degree graph} of $G$: this is the (simple, undirected) graph whose vertices are the…

Group Theory · Mathematics 2022-09-16 S. Dolfi , E. Pacifici , L. Sanus

A supercharacter theory for a finite group $G$ is a set of superclasses each of which is a union of conjugacy classes together with a set of sums of irreducible characters called supercharacters that together satisfy certain compatibility…

Group Theory · Mathematics 2016-05-31 Ali Reza Ashrafi , Fatemeh Koorepazan-Moftakhar

Let $G$ be a finite group, and let $\text{Irr}(G)$ denote the set of the irreducible complex characters of $G$. An element $g\in G$ is called a vanishing element of $G$ if there exists $\chi\in\text{Irr}(G)$ such that $\chi(g)=0$ (i.e., $g$…

Group Theory · Mathematics 2024-09-24 Mark L. Lewis , Lucia Morotti , Emanuele Pacifici , Lucia Sanus , Hung P. Tong-Viet

For an irreducible character $\chi$ of a finite group $G$, its kernel is defined as $\text{ker }\chi=\{g\in G: \chi(g)=\chi(1)\}$. In this paper we characterize the finite groups of prime power order(for odd prime) in which kernels of all…

Group Theory · Mathematics 2025-12-23 Nabajit Talukdar

Let $G$ be a finite group and $\mathrm{Irr}(G)$ be the set of all complex irreducible characters of $G$. The character-graph $\Delta(G)$ associated to $G$, is a graph whose vertex set is the set of primes which divide the degrees of some…

Group Theory · Mathematics 2021-09-27 Mahdi Ebrahimi , Maryam Khatami , Zohreh Mirzaei

We develop the concept of character level for the complex irreducible characters of finite, general or special, linear and unitary groups. We give characterizations of the level of a character in terms of its Lusztig's label and in terms of…

Representation Theory · Mathematics 2020-02-19 Robert M. Guralnick , Michael Larsen , Pham Huu Tiep

For every finite quasisimple group of Lie type $G$, every irreducible character $\chi$ of $G$, and every element $g$ of $G$, we give an exponential upper bound for the character ratio $|\chi(g)|/\chi(1)$ with exponent linear in $\log_{|G|}…

Representation Theory · Mathematics 2024-03-15 Michael Larsen , Pham Huu Tiep

We establish new bounds on character values and character ratios for finite groups $G$ of Lie type, which are considerably stronger than previously known bounds, and which are best possible in many cases. These bounds have the form…

Group Theory · Mathematics 2017-07-14 Roman Bezrukavnikov , Martin W. Liebeck , Aner Shalev , Pham Huu Tiep

T.C. Burness and S.D. Scott \cite{3} classified finite groups $G$ such that the number of prime order subgroups of $G$ is greater than $|G|/2-1$. In this note, we study finite groups $G$ whose subgroup graph contains a vertex of degree…

Group Theory · Mathematics 2025-02-05 Marius Tărnăuceanu