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Using the construction by Bencs and T\'{o}th of invariant random subgroups on weakly branch groups acting on regular rooted trees we produce uncountably many indecomposable characters on these groups. In fact, we study three types of…

Representation Theory · Mathematics 2023-12-21 Artem Dudko , Rostislav Grigorchuk

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

We define the superclasses for a classical finite unipotent group $U$ of type $B_{n}(q)$, $C_{n}(q)$, or $D_{n}(q)$, and show that, together with the supercharacters defined in a previous paper, they form a supercharacter theory. In…

Group Theory · Mathematics 2008-10-31 Carlos A. M. Andre , Ana Margarida Neto

Given an almost simple group $A$, we algorithmically show that the character table of $A$ determines whether or not the Sylow 3-subgroups of $A$ are 2-generated. We show this property is equivalent to a condition involving the Galois action…

Group Theory · Mathematics 2026-04-24 Eden Ketchum

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

We construct the supercharacter theory for the finite groups of triangular type. Its special case is the supercharacter theory for algebra groups of P.Diaconis and I.M.Isaacs. The supercharacter analog of the A.A. Kirillov formula for…

Representation Theory · Mathematics 2015-08-25 A. N. Panov

In this paper, we prove that a refinement of the Alperin-McKay Conjecture for $p$-blocks of finite groups, formulated by I. M. Isaacs and G. Navarro in 2002, holds for all covering groups of the symmetric and alternating groups, whenever…

Representation Theory · Mathematics 2013-01-09 Jean-Baptiste Gramain

As a sequel to [CS13b], we verify the so-called inductive AM-condition introduced in [Sp12] for simple groups of type A and blocks with maximal defect. This is part of the program set up to verify the Alperin-McKay conjecture through its…

Representation Theory · Mathematics 2014-03-20 Marc Cabanes , Britta Spaeth

We show that the largest character degree of an alternating group $A_n$ with $n\geq 5$ can be bounded in terms of smaller degrees in the sense that \[ b(A_n)^2<\sum_{\psi\in\textrm{Irr}(A_n),\,\psi(1)< b(A_n)}\psi(1)^2, \] where…

Group Theory · Mathematics 2019-03-05 Zoltán Halasi , Carolin Hannusch , Hung Ngoc Nguyen

For any ordinary irreducible character of a maximal reflection subgroup of type $D_aD_b$ of a type $D$ Weyl group we give an explicit decomposition of the induced character in terms of Littlewood-Richardson coefficients.

Representation Theory · Mathematics 2015-03-16 Jay Taylor

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

If a group $G$ is $\pi$-separable, where $\pi$ is a set of primes, the set of irreducible characters $\operatorname{B}_{\pi}(G) \cup \operatorname{B}_{\pi'}(G)$ can be defined. In this paper, we prove that there are variants of some…

Group Theory · Mathematics 2020-07-14 N. Grittini

We generalize a result by Cunningham-Salmasian to a Mackey-type formula for the compact restriction of a semisimple perverse sheaf produced by parabolic induction from a character sheaf, under certain conditions on the parahoric group used…

Representation Theory · Mathematics 2010-11-09 Pramod N. Achar , Clifton L. R. Cunningham

C. Andre and N. Yan introduced the idea of a supercharacter theory to give a tractable substitute for character theory in wild groups such as the unipotent uppertriangular group $U_n(F_q)$. In this theory superclasses are certain unions of…

Representation Theory · Mathematics 2007-05-23 Persi Diaconis , Nathaniel Thiem

Recently, a strong exponential character bound has been established in [3] for all elements $g \in \mathbf{G}^F$ of a finite reductive group $\mathbf{G}^F$ which satisfy the condition that the centraliser $C_{\mathbf{G}}(g)$ is contained in…

Representation Theory · Mathematics 2022-02-07 Jay Taylor , Pham H. Tiep

Let $G$ be a finite group of order divisible by two distinct primes $p$ and $q$. We show that $G$ possesses a non-trivial irreducible character of degree not divisible by $p$ nor $q$ lying in both the principal $p$- and $q$-block whenever…

Representation Theory · Mathematics 2025-07-01 Annika Bartelt

We investigate character degree graphs of solvable groups. In particular, we provide general results that can be used to eliminate which degree graphs can occur as solvable groups. Finally, we show a specific family of graphs cannot occur…

Representation Theory · Mathematics 2024-02-28 Mark W. Bissler , Jacob Laubacher , Mark L. Lewis

We prove that if $p$ is an odd prime, $G$ is a solvable group, and the average value of the irreducible characters of $G$ whose degrees are not divisible by $p$ is strictly less than $2(p+1)/(p+3)$, then $G$ is $p$-nilpotent. We show that…

Group Theory · Mathematics 2015-07-02 Mark L. Lewis

The theory of supercharacters, which generalizes classical character theory, was recently introduced by P. Diaconis and I.M. Isaacs, building upon earlier work of C. Andre. We study supercharacter theories on $(Z/nZ)^d$ induced by the…

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
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