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The representation dimension of a finite group G is the smallest positive integer m for which there exists an embedding of G in GL_m(C). In this paper we find the largest value of representation dimensions, as Granges over all groups of…

Representation Theory · Mathematics 2010-11-22 Shane Cernele , Masoud Kamgarpour , Zinovy Reichstein

The Cremona dimension of a group $G$ is the minimal $n$ such that $G$ is isomorphic to a subgroup of the Cremona group of birational transformations of an $n$-dimensional rational variety. In this survey article, we give many examples that…

Algebraic Geometry · Mathematics 2026-05-04 Igor Dolgachev

We give new, explicit and asymptotically sharp, lower bounds for dimensions of irreducible modular representations of finite symmetric groups.

Representation Theory · Mathematics 2019-09-10 Alexander Kleshchev , Lucia Morotti , Pham Huu Tiep

A complete list of one dimensional groups definable in the p-adic numbers is given, up to a finite index subroup and a quotient by a finite subgroup.

Logic · Mathematics 2023-06-22 Juan Pablo Acosta López

We classify the irreducible projective representations of symmetric and alternating groups of minimal possible and second minimal possible dimensions, and get a lower bound for the third minimal dimension. On the way we obtain some new…

Representation Theory · Mathematics 2011-12-19 Alexander S. Kleshchev , Pham Huu Tiep

We classify globally irreducible representations of alternating groups and double covers of symmetric and alternating groups. In order to achieve this classification we also completely characterise irreducible representations of such groups…

Representation Theory · Mathematics 2024-10-29 Matthew Fayers , Lucia Morotti

In this paper we consider two functions related to the arithmetic and geometric means of element orders of a finite group, showing that certain lower bounds on such functions strongly affect the group structure. In particular, for every…

Group Theory · Mathematics 2023-03-07 Valentina Grazian , Carmine Monetta , Marialaura Noce

The representation dimension of a finite group $G$ is the minimal dimension of a faithful complex linear representation of $G$. We prove that the representation dimension of any finite group $G$ is at most $\sqrt{|G|}$ except if $G$ is a…

Group Theory · Mathematics 2026-02-18 Alexander Moretó

Identities of complex irreducible representations of finite groups can be explicitly constructed from character value sets. Among other things, these identities determine representations up to Gassmann equivalency. Some examples of…

Representation Theory · Mathematics 2026-01-05 Alexander Kushkuley

We define the notion of accessibility for a pro-$p$ group. We prove that finitely generated pro-$p$ groups are accessible given a bound on the size of their finite subgroups. We then construct a finitely generated inaccessible pro-$p$…

Group Theory · Mathematics 2018-11-07 Gareth Wilkes

A partial group with $n+1$ elements is, when regarded as a symmetric simplicial set, of dimension at most $n$. This dimension is $n$ if and only if the partial group is a group. As a consequence of the first statement, finite partial groups…

Group Theory · Mathematics 2026-03-13 Philip Hackney , Rémi Molinier

Many open conjectures in the representation theory of finite groups can be studied by reducing them to related questions about quasi-simple groups. In such studies, $p$-radical subgroups typically play a critical role. To classify the…

Group Theory · Mathematics 2026-01-06 Meizheng Fu

We give a formula for the essential dimension of a cohomology class $\alpha$ in $H^d(K, \mathbb{Q}_p/\mathbb{Z}_p (d))$ when $K$ is a strictly Henselian field. This formula is particularly explicit in the case, where $\alpha$ is a Brauer…

Group Theory · Mathematics 2024-01-17 Danny Ofek , Zinovy Reichstein

We provide polynomial lower bounds for residual finiteness of residually finite, finitely generated solvable groups that admit infinite order elements in the Fitting subgroup of strict distortion at least exponential. For this class of…

Group Theory · Mathematics 2019-12-03 Mark Pengitore

In this paper, we compute the essential $2$-dimension when the defining prime is odd of the general linear groups, the projective general linear groups, the special linear groups when $n$ is odd or $n = 2$, as well as the special linear…

Group Theory · Mathematics 2025-08-06 Hannah Knight

In a finite real reflection group, the reflection length of each element is equal to the codimension of its fixed space, and the two coincident functions determine a partial order structure called the absolute order. In complex reflection…

Combinatorics · Mathematics 2025-05-20 Joel Brewster Lewis , Jiayuan Wang

This paper investigates the critical group of a faithful representation of a finite group. It computes the order of the critical group in terms of the character values, and gives some restrictions on its subgroup structure. It also computes…

Combinatorics · Mathematics 2016-10-14 Christian Gaetz

We give an upper bound for the essential dimension of a smooth unipotent algebraic group over an arbitrary field. We also show that over a field $k$ which is finitely generated over a perfect field, a smooth unipotent algebraic $k$-group is…

Number Theory · Mathematics 2010-12-15 Nguyen Duy Tan

We describe a straightforward construction of the pseudo-split absolutely pseudo-simple groups of minimal type with irreducible root systems of type $BC_n$; these exist only in characteristic $2$. We also give a formula for the dimensions…

Group Theory · Mathematics 2024-01-09 Michael Bate , Gerhard Röhrle , Damian Sercombe , David I. Stewart

The essential dimension $\operatorname{ed}_k({\rm S}_n)$ of the symmetric group ${\rm S}_n$ is the minimal integer $d$ such that the general polynomial $x^n + a_1 x^{n-1} + \ldots + a_n$ can be reduced to a $d$-parameter form by a…

Algebraic Geometry · Mathematics 2023-08-22 Oakley Edens , Zinovy Reichstein