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We prove a convolution formula for the conjugacy classes in symmetric groups conjectured by the second author. A combinatorial interpretation of coefficients is provided. As a main tool we introduce new semigroup of partial permutations. We…

Combinatorics · Mathematics 2007-05-23 Vladimir Ivanov , Sergei Kerov

Let $G$ be a reductive algebraic group over an algebraically closed field $k$ of prime characteristic not $2$, whose Lie algebra is denoted $\mathfrak{g}$. We call a subvariety $\mathfrak{X}$ of the nilpotent cone $N \subset \mathfrak{g}$…

Representation Theory · Mathematics 2025-05-28 Simon M. Goodwin , Rachel Pengelly , David I. Stewart , Adam R. Thomas

Let $K$ be an algebraically closed field of characteristic $0$. In this paper we classify the $\text{PGL}_3(K)$-conjugacy classes of semi-stable dominant degree $2$ rational maps $f:{\mathbb P}^2_K\dashrightarrow{\mathbb P}^2_K$ whose…

Algebraic Geometry · Mathematics 2017-08-29 Michelle Manes , Joseph H. Silverman

Symmetric $k$-varieties generalize Riemannian sym\-me\-tric spaces to reductive groups defined over arbitrary fields. For most perfect fields, it is known that symmetric $k$-varieties are in one-to-one correspondence with isomorphy classes…

Group Theory · Mathematics 2015-10-02 Nathaniel Schwartz

The genus spectrum of a finite group $G$ is the set of all $g\geq 2$ such that $G$ acts faithfully and orientation-preserving on a closed compact orientable surface of genus $g$. This article is an overview of some results relating the…

Group Theory · Mathematics 2013-09-04 Jürgen Müller , Siddhartha Sarkar

Let ${\rm GK}(G)$ be the prime graph associated with a finite group $G$ and $D(G)$ be the degree pattern of $G$. A finite group $G$ is said to be $k$-fold OD-characterizable if there exist exactly $k$ non-isomorphic groups $H$ such that…

Group Theory · Mathematics 2017-05-23 B. Akbari , A. R. Moghaddamfar

Let $S$ be a semigroup. The elements $a,b\in S$ are called primarily conjugate if $a=xy$ and $b=yx$ for certain $x,y\in S$. The relation of conjugacy is defined as the transitive closure of the relation of primary conjugacy. In the case…

Group Theory · Mathematics 2007-05-23 Ganna Kudryavtseva

It is proved that a profinite group $G$ has fewer than $2^{\aleph_0}$ conjugacy classes of $p$-elements for an odd prime $p$ if and only if its $p$-Sylow subgroups are finite. (Here, by a $p$-element one understands an element that either…

Group Theory · Mathematics 2022-09-30 John S. Wilson

Let $\bfG$ be a connected reductive algebraic group defined over $\F_q$, where $q$ is a power of a prime $p$ that is good for $\bfG$. Let $F$ be the Frobenius morphism associated with the $\FF_q$-structure on $\bfG$ and set $G = \bfG^F$,…

Group Theory · Mathematics 2008-07-11 Simon M. Goodwin , Gerhard Roehrle

In this paper we classify filiform associative algebras of degree $k$ over a field of characteristic zero. Moreover, we also classify naturally graded complex filiform and quasi-filiform nilpotent associative algebras which are described by…

Rings and Algebras · Mathematics 2018-08-21 Ikboljon A. Karimjanov , Manuel Ladra

In this paper we classify the isomorphism classes of four dimensional nilpotent associative algebras over a field F, studying regular subgroups of the affine group AGL_4(F). In particular we provide explicit representatives for such classes…

Group Theory · Mathematics 2017-02-17 Marco Antonio Pellegrini

Let X be an irreducible reduced complex space on which a connected compact Lie group K acts by holomorphic automorphisms. Let G be the complexification of K and g the Lie algebra of G. Following the theory of algebraic transformation…

Complex Variables · Mathematics 2007-05-23 D. Akhiezer , P. Heinzner

We consider groups $G$ such that the set $[G,\varphi]=\{g^{-1}g^{\varphi}|g\in G\}$ is a subgroup for every automorphism $\varphi$ of $G$, and we prove that there exists such a group $G$ that is finite and nilpotent of class $n$ for every…

Group Theory · Mathematics 2024-05-15 Chiara Nicotera

Automorphisms of order $2$ are studied in order to understand generalized symmetric spaces. The groups of type $E_6$ we consider here can be realized as both the group of linear maps that leave a certain determinant invariant, and also as…

Group Theory · Mathematics 2016-01-05 John Hutchens

We show that for any integer n and any field k of characteristic different from 2 there are at most finitely many isomorphism classes of quadratic morphisms from the projective line over k to itself with a finite postcritical orbit of size…

Algebraic Geometry · Mathematics 2013-08-27 Richard Pink

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

We will consider a two dimensional "symmetric" subfamily of the four dimensional family of Fricke cubic surfaces. The main result is that such symmetric cubic surfaces arise as character varieties for the exceptional group of type G_2.…

Algebraic Geometry · Mathematics 2014-10-02 Philip Boalch , Robert Paluba

A first characterization of the isomorphism classes of $k$-involutions for any reductive algebraic groups defined over a perfect field was given by Helminck in 2000 using $3$ invariants. In 2004, Helminck, Wu, and Dometrius gave a full…

Representation Theory · Mathematics 2014-07-16 Robert W. Benim , Aloysius G. Helminck , Farrah Jackson

We prove that over an algebraically closed field $\mathbb{K}$ of characteristic different from $2$, the group algebra $R=\mathbb{K} D_\infty$ of the infinite dihedral group $D_\infty$ has exactly six conjugacy classes of involutions…

Group Theory · Mathematics 2023-10-17 Ivan Dimitrov , Charles Paquette , David Wehlau , Tianyuan Xu

We determine which simple algebraic groups of type $^3D_4$ over arbitrary fields of characteristic different from 2 admit outer automorphisms of order 3, and classify these automorphisms up to conjugation. The criterion is formulated in…

Group Theory · Mathematics 2014-09-08 Max-Albert Knus , Jean-Pierre Tignol