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We classify the finite dimensional irreducible representations with integral central character of finite $W$-algebras $U(\mathfrak g,e)$ associated to standard Levi nilpotent orbits in classical Lie algebras of types B and C. This…

Representation Theory · Mathematics 2016-01-20 Jonathan Brown , Simon M. Goodwin

Let $G$ be a reductive group with Borel $B$ and Weyl group $W$. Then $B$-double cosets in $G$ are indexed by the Weyl group, say $O(w)$ for $w\in W$. Then we prove the minimal $B$-double coset in the convolution $O(w_1)*O(w_2)$ is…

Representation Theory · Mathematics 2025-03-26 Kenta Suzuki

We establish a connection between constructible representations (arising in the study of left cells in Weyl groups) and Catalan numbers.

Representation Theory · Mathematics 2024-03-06 George Lusztig , Eric Sommers

We define a family of universal finite-dimensional highest weight modules for affine Lie algebras, we call these Weyl modules. We conjecture that these are the classical limits of the irreducible finite--dimensional representations of the…

Quantum Algebra · Mathematics 2007-05-23 Vyjayanthi Chari , Andrew Pressley

This note discusses the bijection between the exceptional subcategories of representations of quivers and generalized non-crossing partitions of Weyl groups. We give a new proof of the Ingalls-Thomas-Igusa-Schiffler bijection by using the…

Representation Theory · Mathematics 2016-01-29 Anningzhe Gao

In [APS], the authors characterize the partitions of $n$ whose corresponding representations of $S_n$ have nontrivial determinant. The present paper extends this work to all irreducible finite Coxeter groups $W$. Namely, given a nontrivial…

Representation Theory · Mathematics 2017-10-10 Debarun Ghosh , Steven Spallone

Let ${\mathcal O}$ be an involutive discrete valuation ring with residue field of characteristic not 2. Let $A$ be a quotient of ${\mathcal O}$ by a nonzero power of its maximal ideal and let $*$ be the involution that $A$ inherits from…

Representation Theory · Mathematics 2018-05-07 Moumita Shau , Fernando Szechtman

In this paper, we offer a presentation for the Weyl group of an affine reflection system $R$ of type $A_1$ as well as a presentation for the so called hyperbolic Weyl group associated with an affine reflection system of type $A_1$. Applying…

Quantum Algebra · Mathematics 2012-07-11 Saeid Azam , Mohammad Nikouei

Let w be an elliptic element of the Weyl group of a connected reductive group G. Let X be the set of pairs (g,B) where g is an element of G, B is a Borel subgroup of G and B,gBg^{-1} are in relative position w. Then G acts naturally on X.…

Representation Theory · Mathematics 2011-01-11 G. Lusztig

Let W be a Coxeter group and L be a weight function on W. Following Lusztig, we have a corresponding decomposition of W into left cells, which have important applications in representation theory. We study the case where $W$ is an affine…

Representation Theory · Mathematics 2007-07-30 Jeremie Guilhot

Let G be a connected reductive group over an algebraically closed field of characteristic p. In an earlier paper we defined a surjective map \Phi_p from the set \underline{W} of conjugacy classes in the Weyl group W to the set of unipotent…

Representation Theory · Mathematics 2011-05-03 G. Lusztig

Let W be a Weyl group, presented as a crystallographic reflection group on a Euclidean vector space V, and C an open Weyl chamber. In a recent paper, Waldspurger proved that the images (id-w)(C), for Weyl group elements w, are all disjoint,…

Group Theory · Mathematics 2011-10-10 Eckhard Meinrenken

In an earlier paper by Kazhdan and the author, a map from the set of unipotent classes in a reductive connected group over C to the conjugacy classes in the Weyl group was defined. Here we present some experimental evidence for a possibly…

Representation Theory · Mathematics 2009-07-24 G. Lusztig

Let $W$ be an affine Weyl group, and let $\Bbbk$ be a field of characteristic $p>0$. The diagrammatic Hecke category $\mathcal{D}$ for $W$ over $\Bbbk$ is a categorification of the Hecke algebra for $W$ with rich connections to modular…

Representation Theory · Mathematics 2025-02-10 Amit Hazi

In a previous paper I have defined a new basis for the representation ring of a Weyl group. In this paper we show that the new basis is related to the standard basis by an upper triangular unipotent matrix. We also give a new…

Representation Theory · Mathematics 2019-07-09 G. Lusztig

In this paper we construct a new variant of the Weil representation, associated with a symplectic vector space V defined over a finite field of characteristic two. Our variant is a representation of a bigger group than that of Weil. In the…

Representation Theory · Mathematics 2016-09-08 Shamgar Gurevich , Ronny Hadani

We study representations of the double affine Lie algebra associated to a simple Lie algebra. We construct a family of indecomposable integrable representations and identify their irreducible quotients. We also give a condition for the…

Quantum Algebra · Mathematics 2007-05-23 Vyjayanthi Chari , Thang Le

We consider the finite Weyl groups of classical type -- $W(A_{r})$ for $r \geq 1$, $W(B_{r}) = W(C_{r})$ for $r \geq 2$, and $W(D_{r})$ for $r \geq 4$ -- as supergroups in which the reflections are of odd superdegree. Viewing the…

Representation Theory · Mathematics 2026-04-14 Christopher M. Drupieski , Jonathan R. Kujawa

We give an explanation of the bijection between geometric and arithmetic diagrams attached to supercuspidal unipotent representations of a simple p-adic group which is based purely on algebra. The second version contains much additional…

Representation Theory · Mathematics 2023-11-07 G. Lusztig

In this paper, we classify irreducible representations of affine group superschemes over fields $F$ of characteristic not two in terms of those over a separable closure $F^{\mathrm{sep}}$ and their Galois twists. We also compute the…

Representation Theory · Mathematics 2024-12-30 Takuma Hayashi