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It is known that, if all the real-valued irreducible characters of a finite group have odd degree, then the group has normal Sylow $2$-subgroup. We generalize this result for Sylow $p$-subgroups, for any prime number $p$, while assuming the…

Group Theory · Mathematics 2024-01-17 Nicola Grittini

For an irreducible complex character $\chi$ of a finite group $G$, the codegree of $\chi$ is defined by $|G:\ker(\chi)|/\chi(1)$, where $\ker(\chi)$ is the kernel of $\chi$. Given a prime $p$, we provide a classification of finite groups in…

Group Theory · Mathematics 2025-11-13 Guohua Qian , Yu Zeng

If $G$ is a finite classical group, linear or unitary in any characteristic, and orthogonal in odd characteristic, we give an approximate formula for $\chi(g)$ in which the error term is much smaller than the estimate, when $g\in G$ is an…

Group Theory · Mathematics 2025-07-18 Michael Larsen , Pham Huu Tiep

A super-Brauer character theory of a group $G$ and a prime $p$ is a pair consisting of a partition of the irreducible $p$-Brauer characters and a partition of the $p$-regular elements of $G$ that satisfy certain properties. We classify the…

Group Theory · Mathematics 2017-03-02 Xiaoyou Chen , Mark L. Lewis

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

Let $G$ be a finite group. We consider the set of the irreducible complex characters of $G$, namely $Irr(G)$, and the related degree set $cd(G)=\{\chi(1) : \chi\in Irr(G)\}$. Let $\rho(G)$ be the set of all primes which divide some…

Group Theory · Mathematics 2015-11-25 Roghayeh Hafezieh

Suppose that $G$ is a finite solvable group and let $H$ be a Hall $\pi$-subgroup, let $b(H)$ be the largest character degree of $H$, we show that $|G:O_{\pi' \pi}(G)|_{\pi} \leq b(H)^2$.

Group Theory · Mathematics 2025-10-28 Samarth Das , Yong Yang

Let \chi be an irreducible character of the finite group G. If g is an element of G and \chi(g) is not zero, then we conjecture that the order of g divides |G|/\chi(1). The conjecture is a generalization of the classical fact that…

Representation Theory · Mathematics 2007-05-23 Tom Wilde

In this paper, we first show that the irreducible characters of a quotient table algebra modulo a normal closed subset can be viewed as the irreducible characters of the table algebra itself. Furthermore, we define the character products…

Representation Theory · Mathematics 2015-08-26 J. Bagherian , A. Rahnamai Barghi

The classification of irreducible, spherical characters of the infinite-dimensional unitary/orthogonal/symplectic groups can be obtained by finding all possible limits of normalized, irreducible characters of the corresponding…

Representation Theory · Mathematics 2018-12-18 Cesar Cuenca , Vadim Gorin

Let G be a finite group and N be a non-trivial normal subgroup of G, such that the average character degree of irreducible characters in Irr(G|N) is less than or equal to 16=5. Then we prove that N is solvable. Also, we prove the…

Group Theory · Mathematics 2021-09-10 Zeinab Akhlaghi

Several recent problems in the representation theory of finite groups require determining whether certain characters of almost simple groups belong to the principal block. Since the values of these characters are not yet known, we employ…

Representation Theory · Mathematics 2025-08-05 Richard Lyons , J. Miquel Martínez , Gabriel Navarro , Pham Huu Tiep

Together with David Schlang we computed the discriminants of the invariant Hermitian forms for all indicator $o$ even degree absolutely irreducible characters of the ATLAS groups supplementing the tables of orthogonal determinants computed…

Representation Theory · Mathematics 2025-11-04 Gabriele Nebe

The structure of the character degree graphs $\Delta(G)$, i.e. the prime graphs on the set $\mathrm{cd}(G)$ of the irreducible character degrees of a finite group $G$, such that $G$ is solvable and $\Delta(G)$ has diameter three, remains an…

Group Theory · Mathematics 2024-03-01 Silvio Dolfi , Roghayeh Hafezieh , Pablo Spiga

A character of a group is said to be super-monomial if every primitive character inducing it is linear. It is conjectured by Isaacs that every irreducible character of an odd $M$-group is super-monomial. We show that all non linear…

Group Theory · Mathematics 2019-04-30 Joakim Færgeman

We define the position of an irreducible complex character of a finite group as an alternative to the degree. We then use this to define three classes of groups: PR-groups, IPR-groups and weak IPR-groups. We show that IPR-groups and weak…

Group Theory · Mathematics 2014-12-18 Tobias Kildetoft

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

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

Let $G$ be a $p$-group and let $\chi$ be an irreducible character of $G$. The codegree of $\chi$ is given by $|G:\text{ker}(\chi)|/\chi(1)$. If $G$ is a maximal class $p$-group that is normally monomial or has at most three character…

Group Theory · Mathematics 2018-09-21 Sarah Croome , Mark L. Lewis

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

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