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Related papers: Note on affine Deligne-Lusztig varieties

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We prove an explicit degree formula for certain unitary Deligne-Lusztig varieties. Combining with an alternative degree formula in terms of Schubert calculus, we deduce several algebraic combinatorial identities which may be of independent…

Algebraic Geometry · Mathematics 2023-01-24 Chao Li

The main purpose of this paper is to prove a group-theoretic generalization of a theorem of Katz on isocrystals. Along the way we reprove the group-theoretic generalization of Mazur's inequality for isocrystals due to Rapoport-Richartz, and…

Representation Theory · Mathematics 2007-05-23 Robert E. Kottwitz

We establish a dimension formula for certain union $X^G(\mu,b)_J$ of affine Deligne-Lusztig varieties associated to arbitrary parahoric level structures of split reductive groups, under certain genericity hypotheses.

Representation Theory · Mathematics 2024-06-26 Arghya Sadhukhan

George Lusztig conjectured that asymptotic affine Hecke algebra of a simply connected group can be explicitly described in terms of convolution algebras. Main Theorem of this note (which is a continuation of RT/0010089) is a weak version of…

Representation Theory · Mathematics 2007-05-23 Roman Bezrukavnikov , Viktor Ostrik

In this article we study the cohomology of deep level Deligne--Lusztig varieties of Coxeter type, attached to a reductive group over a local non-archimedean field, which splits over an unramified extension. This allows to construct some new…

Representation Theory · Mathematics 2024-12-10 Alexander B. Ivanov , Sian Nie , Panjun Tan

We study the quotient of parabolic Deligne-Lusztig varieties by a finite unipotent group U^F where U is the unipotent radical of a rational parabolic subgroup P = L U. We show that in some particular cases the cohomology of this quotient…

Representation Theory · Mathematics 2011-12-22 Olivier Dudas

Our concern in this paper is the dimension and inclusion relations of Schubert varieties in twisted partial affine flag varieties. In the end we apply our results to some local models of certain Schubert varieties.

Algebraic Geometry · Mathematics 2010-11-25 Timo Richarz

We prove a 1979 conjecture of Lusztig on the cohomology of semi-infinite Deligne--Lusztig varieties attached to division algebras over local fields. We also prove the two conjectures of Boyarchenko on these varieties. It is known that in…

Representation Theory · Mathematics 2017-10-03 Charlotte Chan

We study finite dimensional approximations to degenerate versions of affine flag varieties using quiver Grassmannians for cyclic quivers. We prove that they admit cellular decompositions parametrized by affine Dellac configurations, and…

Algebraic Geometry · Mathematics 2024-11-08 Alexander Pütz

We study subvarieties of the flag variety called Hessenberg varieties, defined by certain linear conditions. These subvarieties arise naturally in applications including geometric representation theory, number theory, and numerical…

Algebraic Geometry · Mathematics 2007-05-23 Julianna S. Tymoczko

Using Deodhar's decomposition of a double Schubert cell, we study the regular representations of finite groups of Lie type arising in the cohomology of Deligne-Lusztig varieties associated to tori. We deduce that the Deligne-Lusztig…

Representation Theory · Mathematics 2010-11-23 Olivier Dudas

We formulate and prove a non-abelian analog of Deligne's Fixed Part theorem on Hodge classes, revisiting previous work of Jost--Zuo, Katzarkov--Pantev and Landesman--Litt. To this aim we study algebraically isomonodromic extensions of local…

Algebraic Geometry · Mathematics 2026-01-19 Hélène Esnault , Moritz Kerz

The aim of this paper is to give a new explicit construction of Lusztig's asymptotic algebra in affine type $\mathsf{A}$. To do so, we construct a balanced system of cell modules, prove an asymptotic version of the Plancherel Theorem and…

Representation Theory · Mathematics 2026-03-24 Nathan Chapelier-Laget , Jérémie Guilhot , Eloise Little , James Parkinson

Revised: just some typos, reorganized a bit the article. It will be published in the VIASM Annual meeting, Hanoi. We give a detailed account of Deligne's letter to Drinfeld dated June 18, 2011, in which he shows that there are finitely many…

Algebraic Geometry · Mathematics 2012-12-03 Hélène Esnault , Moritz Kerz

We prove a character formula for some closed fine Deligne-Lusztig varieties. We apply it to compute fixed points for fine Deligne-Lusztig varieties arising from the basic loci of Shimura varieties of Coxeter type. As an application, we…

Number Theory · Mathematics 2020-01-22 Xuhua He , Chao Li , Yihang Zhu

Deep level Deligne--Lusztig representations, which are natural analogues of classical Deligne--Lusztig representations, recently play an important role in geometrization of irreducible supercuspidals of $p$-adic groups. In this paper, we…

Representation Theory · Mathematics 2026-01-13 Alexander B. Ivanov , Sian Nie

In 1979, Lusztig proposed a cohomological construction of supercuspidal representations of reductive $p$-adic groups, analogous to Deligne-Lusztig theory for finite reductive groups. In this paper we establish a new instance of Lusztig's…

Representation Theory · Mathematics 2015-07-27 Charlotte Chan

Let $G$ be a connected reductive algebraic group defined over an algebraic closure of a finite field and let $F : G \to G$ be an endomorphism such that $F^d$ is a Frobenius endomorphism for some $d \geq 1$. Let $P$ be a parabolic subgroup…

Group Theory · Mathematics 2008-07-07 Cédric Bonnafé , Raphaël Rouquier

We classify all products of flag varieties with finitely many orbits under the diagonal action of the general linear group. We also classify the orbits in each case and construct explicit representatives. This generalizes the classical…

Algebraic Geometry · Mathematics 2016-09-07 Peter Magyar , Jerzy Weyman , Andrei Zelevinsky

In this article, we study the \'etale cohomology of the compactification of Deligne-Lusztig varieties associated to a Coxeter element. We prove a result for the integral coefficients in the case of general linear group $GL_d$, and we…

Algebraic Geometry · Mathematics 2014-11-06 Haoran Wang