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We construct new examples of derived autoequivalences for a family of higher-dimensional Calabi-Yau varieties. Specifically, we take the total spaces of certain natural vector bundles over Grassmannians G(r,d) of r-planes in a d-dimensional…

Algebraic Geometry · Mathematics 2014-02-26 Will Donovan

In this paper, the first of a series of three, we classify holomorphic principal G-bundles over an elliptic curve, where G is a reductive group. We also study the local and global properties of the moduli space of semistable G-bundles. We…

Algebraic Geometry · Mathematics 2007-05-23 Robert Friedman , John W. Morgan

Let X be a smooth projective curve over an algebraically closed field of characteristic >2. Let Bun_{Mp_2} be the stack of metaplectic bundles on X of rank 2. In this paper we study the derived category of genuine l-adic sheaves on…

Representation Theory · Mathematics 2012-11-22 Sergey Lysenko

Let $M$ be a smooth complex projective toric variety equipped with an action of a torus $T$, such that the complement $D$ of the open $T$--orbit in $M$ is a simple normal crossing divisor. Let $G$ be a complex reductive affine algebraic…

Algebraic Geometry · Mathematics 2015-07-10 Indranil Biswas , Arijit Dey , Mainak Poddar

We construct natural relative compactifications for the relative Jacobian over a family $X/S$ of reduced curves. In contrast with all the available compactifications so far, ours admit a universal sheaf, after an etale base change. Our…

alg-geom · Mathematics 2008-02-03 Eduardo Esteves

Let X be Drinfeld's upper half space of dimension d over a finite extension K of Q_p. We construct for every homogeneous vector bundle F on the projective space P^d a GL_{d+1}(K)-equivariant filtration by closed K-Frechet spaces on F(X).…

Number Theory · Mathematics 2007-06-24 Sascha Orlik

Let f : Y -> X be a morphism of complex projective manifolds, and let F be a subsheaf of the tangent bundle which is closed under the Lie bracket, but not necessarily a foliation. This short paper contains an elementary and very geometric…

Algebraic Geometry · Mathematics 2010-03-30 Stefan Kebekus , Stavros Kousidis , Daniel Lohmann

An $F$-zip over a scheme $S$ over a finite field is a certain object of semi-linear algebra consisting of a locally free module with a descending filtration and an ascending filtration and a $\Frob_q$-twisted isomorphism between the…

Algebraic Geometry · Mathematics 2016-01-20 Richard Pink , Torsten Wedhorn , Paul Ziegler

The Green-Griffiths-Lang conjecture says that for every complex projective algebraic variety $X$ of general type there exists a proper algebraic subvariety of $X$ containing all nonconstant entire holomorphic curves $f:\mathbb{C} \to X$. We…

Algebraic Geometry · Mathematics 2015-09-17 Gergely Berczi

Let $G$ be a complex reductive group. The spherical Hecke category of $G$ can be presented as the category of $G_{\mathcal O}$-equivariant constructible sheaves on the affine Grassmannian $\mathrm{Gr}_G$. This category admits a convolution…

Algebraic Geometry · Mathematics 2025-05-22 Guglielmo Nocera

We study the equivariant generalization of topological strings on toric manifolds, focusing in particular on defining the contributions of constant maps in the genus expansion of the partition function. This approach regularizes the…

High Energy Physics - Theory · Physics 2025-12-05 Luca Cassia , Kiril Hristov

This paper begins the project of defining Arthur packets of all unipotent representations for the $p$-adic exceptional group $G_2$. Here we treat the most interesting case by defining and computing Arthur packets with component group $S_3$.…

Representation Theory · Mathematics 2021-11-15 Clifton Cunningham , Andrew Fiori , Qing Zhang

The dual stable Grothendieck polynomials $g_\lambda$ and their sums $\sum_{\mu\subset\lambda} g_\mu$ (which represent $K$-homology classes of boundary ideal sheaves and structure sheaves of Schubert varieties in the Grassmannians) have the…

Combinatorics · Mathematics 2018-08-08 Motoki Takigiku

Let $G$ be a complex, connected, reductive, algebraic group, and $\chi:\mathbb{C}^\times \to G$ be a fixed cocharacter that defines a grading on $\mathfrak{g}$, the Lie algebra of $G$. Let $G_0$ be the centralizer of…

Representation Theory · Mathematics 2020-07-27 Tamanna Chatterjee

For $S$ a closed surface of genus $g\geq2$, we construct a canonical diffeomorphism from the degree $3$ Fock-Thomas space $\mathcal{T}^3(S)$ of higher complex structures to the $\text{SL}(3,\mathbb{R})$ Hitchin component. Our construction…

Geometric Topology · Mathematics 2022-04-12 Alexander Nolte

We show that log flat torsors over a family $X/S$ of nodal curves under a finite flat commutative group scheme $G/S$ are classified by maps from the Cartier dual of $G$ to the log Jacobian of $X$. We deduce that fppf torsors on the smooth…

Algebraic Geometry · Mathematics 2025-06-27 Sara Mehidi , Thibault Poiret

We establish a purely geometric form of the concentration theorem (also called localization theorem) for actions of a linearly reductive group $G$ on an affine scheme $X$ over an affine base scheme $S$. It asserts the existence of a…

Algebraic Geometry · Mathematics 2025-03-27 Olivier Haution

Deligne constructed a remarkable local system on $\bP^1-\{0,\infty\}$ attached to a family of Kloosterman sums. Katz calculated its monodromy and asked whether there are Kloosterman sheaves for general reductive groups and which automorphic…

Algebraic Geometry · Mathematics 2010-06-17 Jochen Heinloth , Ngo Bao Chau , Zhiwei Yun

We call a sheaf on an algebraic variety immaculate if it lacks any cohomology including the zero-th one, that is, if the derived version of the global section functor vanishes. Such sheaves are the basic tools when building exceptional…

Algebraic Geometry · Mathematics 2018-08-29 Klaus Altmann , Jarosław Buczyński , Lars Kastner , Anna-Lena Winz

We first give an exposition of how the Polyakov path integral for the bosonic string produces a natural mapping class group invariant measure, $d(Poly)$, on the Teichm\"uller space of Riemann surfaces of each fixed genus. The description of…

alg-geom · Mathematics 2008-02-03 Subhashis Nag