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Based upon the general theory, developed by the author, on the parametrization of the irreducible representations of the hyper special compact groups corresponding to the regular adjoint orbit, supercuspidal representations of $SL_n(F)$ are…

Representation Theory · Mathematics 2021-09-28 Koichi Takase

Extended affine root systems appear as the root systems of extended affine Lie algebras. A subclass of extended affine root systems, whose elements are called ``minimal" turns out to be of special interest mostly because of the geometric…

Quantum Algebra · Mathematics 2023-08-15 Saeid Azam , Fatemeh Parishani , Shaobin Tan

We construct Lie algebras arising from cubic norm pairs over arbitrary commutative base rings. Such Lie algebras admit a grading by a root system of type $G_2$, and when the cubic norm pair is a cubic Jordan matrix algebra, the…

Rings and Algebras · Mathematics 2026-02-09 Tom De Medts , Torben Wiedemann

We prove that an irreducible lattice in a semisimple algebraic group is virtually isomorphic to an arithmetic lattice if and only if it admits a faithful self-similar action on a rooted tree of finite valency.

Group Theory · Mathematics 2008-09-05 Michael Kapovich

In previous papers, the author showed that in many cases of interest there exists an isomorphism between certain path algebras related to the structure of the subregular J-rings of Coxeter systems and matrix rings over a free product of…

Rings and Algebras · Mathematics 2025-12-05 Annette Pilkington

The vertices of the four dimensional $120$-cell form a non-crystallographic root system whose corresponding symmetry group is the Coxeter group $H_{4}$. There are two special coordinate representations of this root system in which they and…

Group Theory · Mathematics 2017-08-25 Robert V. Moody , Jun Morita

Given a Hopf algebra $A$ graded by a discrete group together with an action of the same group preserving the grading, we define a new Hopf algebra, which we call the graded twisting of $A$. If the action is adjoint, this new Hopf algebra is…

Quantum Algebra · Mathematics 2021-06-10 Julien Bichon , Sergey Neshveyev , Makoto Yamashita

Let $\Fth$ be a $\Bk$-graph on a single vertex. We show that every irreducible atomic $*$-representation is the minimal $*$-dilation of a group construction representation. It follows that every atomic representation decomposes as a direct…

Operator Algebras · Mathematics 2008-04-25 Kenneth R. Davidson , Dilian Yang

In this paper we answer a question of Gabriel Navarro about orbit sizes of a finite linear group H acting completely reducibly on a vector space V: if the orbits containing the vectors a and b have coprime lengths m and n, we prove that the…

Group Theory · Mathematics 2011-12-22 Silvio Dolfi , Robert Guralnick , Cheryl Praeger , Pablo Spiga

We apply the loop module construction of arXiv:1504.05114 in the context of Lie colour algebras. We construct a bijection between the equivalence classes of all finite-dimensional graded irreducible Lie colour algebra representations from…

Mathematical Physics · Physics 2024-07-30 Mitchell Ryan

As a first application of the double affine Hecke algebra with unequal parameters on Weyl orbits to representation theory of semisimple Lie algebras, we find the graded multiplicities of the trivial module and of the little adjoint module…

Representation Theory · Mathematics 2018-06-06 Ibukun Ademehin

We provide a uniform bound for the index of cohomology classes in $H^i(F, \mu_\ell^{\otimes i-1})$ when $F$ is a semiglobal field (i.e., a one-variable function field over a complete discretely valued field $K$). The bound is given in terms…

Number Theory · Mathematics 2023-06-21 David Harbater , Julia Hartmann , Daniel Krashen

We present several new examples of reflection principles which apply to both class groups of number fields and picard groups of of curves over $\mathbb{P}^{1}/\mathbb{F}_{p}$. This proves a conjecture of Lemmermeyer about equality of 2-rank…

Number Theory · Mathematics 2016-05-17 Jack Klys

We study higher rank Jacobi partial and false theta functions (generalizations of the classical partial and false theta functions) associated to positive definite rational lattices. In particular, we focus our attention on certain Kostant's…

Quantum Algebra · Mathematics 2019-02-19 Thomas Creutzig , Antun Milas

In any Coxeter group, the conjugates of elements in its Coxeter generating set are called reflections and the reflection length of an element is its length with respect to this expanded generating set. In this article we give a simple…

Combinatorics · Mathematics 2020-03-02 Joel Brewster Lewis , Jon McCammond , T. Kyle Petersen , Petra Schwer

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

We provide a dual version of the Geck--Rouquier Theorem on the center of an Iwahori--Hecke algebra, which also covers the complex case. For the eight complex reflection groups of rank $2$, for which the symmetrising trace conjecture is…

Representation Theory · Mathematics 2023-03-17 Eirini Chavli , Götz Pfeiffer

We introduce a notion of elliptic fake degrees for unipotent elliptic representations of a semisimple p-adic group. We conjecture, and verify in some cases, that the relation between the formal degrees of unipotent discrete series…

Representation Theory · Mathematics 2015-06-12 Dan Ciubotaru , Eric M. Opdam

We show that the Hurwitz action is "as transitive as possible" on reflection factorizations of Coxeter elements in the well-generated complex reflection groups $G(d, 1, n)$ (the group of $d$-colored permutations) and $G(d, d, n)$.

Combinatorics · Mathematics 2020-06-29 Joel Brewster Lewis

The formal degree conjecture and the root number conjecture are verified with respect to supercuspidal representations of $Sp_{2n}(F)$ and $L$-parameters associated with tamely ramified extension $K/F$ of degree $2n$. The supercuspidal…

Representation Theory · Mathematics 2022-05-24 Koichi Takase