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We determine the finite groups whose real irreducible representations have different degrees.

Group Theory · Mathematics 2025-05-08 Thomas Breuer , Frank Calegari , Silvio Dolfi , Gabriel Navarro , Pham Huu Tiep

There has been some interest on how the average character degree affects the structure of a finite group. We define, and denote by $ \mathrm{anz}(G) $, the average number of zeros of characters of a finite group $ G $ as the number of zeros…

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

The covering number of a non-linear character $\chi$ of a finite group $G$ is the least positive integer $k$ such that every irreducible character of $G$ occurs in $\chi^k$. We determine the covering numbers of irreducible characters of the…

Representation Theory · Mathematics 2024-07-08 Rijubrata Kundu , Velmurugan S

We classify, up to conjugacy, the finite subgroups of PGL(2,K) of order prime to char(K).

Algebraic Geometry · Mathematics 2009-09-23 Arnaud Beauville

In this note we study a class of finite groups for which the orders of subgroups satisfy a certain inequality. In particular, characterizations of the well-known groups $\mathbb{Z}_2\times\mathbb{Z}_2$ and $S_3$ are obtained.

Group Theory · Mathematics 2016-10-27 Marius Tarnauceanu

For a finite group $G$, we denote by $c(G)$, the minimal degree of faithful representation of $G$ by quasi-permutation matrices over the complex field $\mathbb{C}$. For an irreducible character $\chi$ of $G$, the codegree of $\chi$ is…

Group Theory · Mathematics 2023-06-12 Sunil Kumar Prajapati , Ayush Udeep

For a finite group $G$ and complex character $\chi\in\mathrm{Irr}(G)$ that restricts irreducibly to a normal subgroup $N\vartriangleleft G,$ we prove a theorem about Clifford correspondences between the characters of subgroups of $G$ that…

Representation Theory · Mathematics 2018-06-12 Tom Wilde

Let $G$ be a finite group. We study the generalized character defined by $\Xi(g)=|G|o(g)$, for $g\in G$, which is closely related to a function that has been very studied recently from a group theoretical point of view.

Group Theory · Mathematics 2023-12-04 Alexander Moretó

In this paper we classify all finite 2-groups of class 2 for which every automorphism of order 2 leaving the Frattini subgroup elementwise fixed is inner. We prove that every such group G is isomorphic to Q(n; r) = <a, b| a^{2n}= b^{2r}= 1;…

Group Theory · Mathematics 2012-12-05 A. Abdollahi , M. Ahmadi , S. M. Ghoraishi

Given a finite group $G$, we denote by $L(G)$ the subgroup lattice of $G$ and by ${\rm Isolated}(G)$ the set of isolated subgroups of $G$. In this note, we describe finite groups $G$ such that $|{\rm Isolated}(G)|=|L(G)|-k$, where…

Group Theory · Mathematics 2021-11-30 Marius Tărnăuceanu

We consider the structure of finite $p$-groups $G$ having precisely three characteristic subgroups, namely $1$, $\Phi(G)$ and $G$. The structure of $G$ varies markedly depending on whether $G$ has exponent $p$ or $p^2$, and, in both cases,…

Group Theory · Mathematics 2014-05-26 S. P. Glasby , P. P. Palfy , Csaba Schneider

Let $S$ be a Suzuki group $^2B_2(q^2)$, where $q^2=2^{2f+1}$, $f\geqslant 1$. In this paper, we determine the degrees of the ordinary complex irreducible characters of every group $G$ such that $S\leqslant G\leqslant \Aut(S)$.

Group Theory · Mathematics 2016-08-04 Mehdi Ghaffarzadeh

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

For an irreducible character $\chi$ of a finite group $G$, let $\mathrm{cod}(\chi):=|G: \ker(\chi)|/\chi(1)$ denote the codegree of $\chi$, and let $\mathrm{cod}(G)$ be the set of irreducible character codegrees of $G$. In this note, we…

Group Theory · Mathematics 2025-02-05 Guohua Qian , Yu Zeng

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 determine the structure of all finite groups $G$ with $K_4$-free character graph…

Group Theory · Mathematics 2019-09-04 Mahdi Ebrahimi

Let $G$ be a finite group and let $\pi$ be a set of primes. Write $\mathrm{Irr}_{\pi'}(G)$ for the set of irreducible characters of degree not divisible by any prime in $\pi$. We show that if $\pi$ contains at most two prime numbers and the…

Representation Theory · Mathematics 2019-03-25 Eugenio Giannelli , Mandi Schaeffer Fry , Carolina Vallejo

In this work, we classify the group gradings on finite-dimensional incidence algebras over a field, where the field has characteristic zero, or the characteristic is greater than the dimension of the algebra, or the grading group is…

Rings and Algebras · Mathematics 2024-02-06 Ednei A. Santulo , Jonathan P. Souza , Felipe Y. Yasumura

This paper is a continuation of [GLT], which develops a level theory and establishes strong character bounds for finite simple groups of linear and unitary type in the case that the centralizer of the element has small order compared to…

Representation Theory · Mathematics 2019-04-23 Robert M. Guralnick , Michael Larsen , Pham Huu Tiep

We define a class of finite groups based on the properties of the closed twins of their power graphs and study the structure of those groups. As a byproduct, we obtain results about finite groups admitting a partition by cyclic subgroups.

Group Theory · Mathematics 2024-12-23 Daniela Bubboloni , Nicolas Pinzauti

Suppose $C(G)$ denotes the set of all cyclic subgroups of a finite group $G$, and $\mathcal{O}_{2}(G)$ denotes the number of elements of order $2$ in $G$. In [Marius T., Finite groups with a certain number of cyclic subgroups. The American…

Group Theory · Mathematics 2025-08-08 Vaibhav Chhajer , Sumana Hatui , Palash Sharma