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This paper studies affine Deligne-Lusztig varieties $X_{\tw}(b)$ in the affine flag variety of a quasi-split tamely ramified group. We describe the geometric structure of $X_{\tw}(b)$ for a minimal length element $\tw$ in the conjugacy…

Algebraic Geometry · Mathematics 2013-09-11 Xuhua He

In this paper, we consider affine Deligne-Lusztig varieties $X_w(b)$ and their certain union $X(\mu,b)$ inside the affine flag variety of a reductive group. Several important results in the study of affine Deligne-Lusztig varieties have…

Representation Theory · Mathematics 2021-10-06 Arghya Sadhukhan

This paper studies affine Deligne-Lusztig varieties in the affine flag manifold of a split group. Among other things, it proves emptiness for certain of these varieties, relates some of them to those for Levi subgroups, extends previous…

Algebraic Geometry · Mathematics 2014-01-14 Ulrich Goertz , Thomas J. Haines , Robert E. Kottwitz , Daniel C. Reuman

Affine Deligne-Lusztig varieties can be thought of as affine analogs of classical Deligne-Lusztig varieties, or Frobenius-twisted analogs of Schubert varieties. We provide a method for proving a non-emptiness statement for affine…

Algebraic Geometry · Mathematics 2016-06-29 E. T. Milićević

Affine Deligne-Lusztig varieties are analogs of Deligne-Lusztig varieties in the context of an affine root system. We prove a conjecture stated in the paper arXiv:0805.0045v4 by Haines, Kottwitz, Reuman, and the first named author, about…

Representation Theory · Mathematics 2010-06-14 Ulrich Goertz , Xuhua He

This paper studies affine Deligne-Lusztig varieties in the affine flag manifold of GL_2. At first we determine all such varieties up to isomorphy. After this we investigate the representations of the sigma-stabilizer of an element b of the…

Algebraic Geometry · Mathematics 2009-10-20 Alexander Ivanov

This paper concerns the dimensions of certain affine Deligne-Lusztig varieties, both in the affine Grassmannian and in the affine flag manifold. Rapoport conjectured a formula for the dimensions of the varieties X_mu(b) in the affine…

Algebraic Geometry · Mathematics 2007-05-23 Ulrich Goertz , Thomas J. Haines , Robert E. Kottwitz , Daniel C. Reuman

The Hecke algebras and quantum group of affine type A admit geometric realizations in terms of complete flags and partial flags over a local field, respectively. Subsequently, it is demonstrated that the quantum group associated to partial…

Representation Theory · Mathematics 2024-03-08 Quanyong Chen , Zhaobing Fan , Qi Wang

Affine Lusztig varieties encode the orbital integrals of Iwahori--Hecke functions and serve as building blocks for the (conjectural) theory of affine character sheaves. We establish a close relationship between affine Lusztig varieties and…

Representation Theory · Mathematics 2024-10-10 Xuhua He

Lusztig varieties are subvarieties in flag manifolds $G/B$ associated to an element $w$ in the Weyl group $W$ and an element $x$ in $G$, introduced in Lusztig's papers on character sheaves. We study the geometry of these varieties when $x$…

Algebraic Geometry · Mathematics 2026-02-02 Patrick Brosnan , Jaehyun Hong , Donggun Lee

In this paper we discuss the geometry of affine Deligne Lusztig varieties with very special level structure, determining their dimension and connected and irreducible components. As application, we prove the Grothendieck conjecture for…

Algebraic Geometry · Mathematics 2020-12-21 Paul Hamacher

We introduce a new language to describe the geometry of affine Deligne-Lusztig varieties in affine flag varieties. This second part of a two paper series uses this new language, i.e. the double Bruhat graph, to describe certain structure…

Representation Theory · Mathematics 2025-09-10 Felix Schremmer

Recently E. Feigin introduced the $\mathbb G_a^N$-degenerations of semisimple algebraic groups and their associated degenerate flag varieties. It has been shown by Feigin, Finkelberg, and Littelmann that the degenerate flag varieties in…

Algebraic Geometry · Mathematics 2013-08-13 Chuck Hague

This note is based on my talk at ICCM 2013, Taipei. We give an exposition of the group-theoretic method and recent results on the questions of non-emptiness and dimension of affine Deligne-Lusztig varieties in affine flag varieties.

Algebraic Geometry · Mathematics 2013-09-03 Xuhua He

Let G be a reductive group over the field F=k((t)), where k is an algebraic closure of a finite field, and let W be the (extended) affine Weyl group of G. The associated affine Deligne-Lusztig varieties $X_x(b)$, which are indexed by…

Algebraic Geometry · Mathematics 2020-08-11 Elizabeth Milićević , Petra Schwer , Anne Thomas

Affine Deligne-Lusztig varieties are analogues of Deligne-Lusztig varieties in the context of affine flag varieties and affine Grassmannians. They are closely related to moduli spaces of $p$-divisible groups in positive characteristic, and…

Algebraic Geometry · Mathematics 2018-02-08 Ulrich Goertz

In this paper we study the geometric structure of affine Deligne-Lusztig varieties for $GL_n$ and $b$ basic. We introduce a new condition on $\lambda$. If this is satisfied, then the corresponding affine Deligne-Lusztig variety is the…

Algebraic Geometry · Mathematics 2022-04-25 Ryosuke Shimada

The affine Deligne-Lusztig variety $X_w(b)$ in the affine flag variety of a reductive group $\mathbb G$ depends on two parameters: the $\sigma$-conjugacy class $[b]$ and the element $w$ in the Iwahori-Weyl group $\tilde W$ of $\mathbb G$.…

Algebraic Geometry · Mathematics 2020-01-13 Xuhua He

The quantum groups of finite and affine type $A$ admit geometric realizations in terms of partial flag varieties of finite and affine type $A$. Recently, the quantum group associated to partial flag varieties of finite type $B/C$ is shown…

Representation Theory · Mathematics 2025-05-28 Zhaobing Fan , Chun-Ju Lai , Yiqiang Li , Li Luo , Weiqiang Wang

We give a new proof of the fact that affine Deligne-Lusztig varieties for an algebraic group of adjoint type, associated with superbasic elements, are of finite type. The proof uses a property of the associated Hecke algebra, which we…

Algebraic Geometry · Mathematics 2012-04-12 Alexander Ivanov
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