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Related papers: Lefschetz Hyperplane Theorem for Stacks

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We give a simple proof of the Riemann-Roch theorem for Deligne-Mumford stacks using the equivariant Riemann-Roch theorem and the localization theorem in equivariant K-theory together with some basic commutative algebra of Artin rings.

Algebraic Geometry · Mathematics 2012-11-13 Dan Edidin

We prove a Hochschild--Konstant--Rosenberg (HKR) theorem for arbitrary derived Deligne--Mumford (DM) stacks, extending the results of Arinkin-C\u{a}ld\u{a}raru-Hablicsek in the smooth, global quotient case, although with different methods.…

Algebraic Geometry · Mathematics 2026-01-21 Lie Fu , Mauro Porta , Sarah Scherotzke , Nicolò Sibilla

We study the orbifold Hirzebruch-Riemann-Roch (HRR) theorem for quotient Deligne-Mumford stacks, explore its relation with the representation theory of finite groups, and derive a new orbifold HRR formula via an orbifold Mukai pairing. As a…

Algebraic Geometry · Mathematics 2024-08-13 Yuhang Chen

The mirror theorem is generalized to any smooth projective variety X. That is, a fundamental relation between the Gromov-Witten invariants of X and Gromov-Witten invariants of complete intersections Y in X is established.

Algebraic Geometry · Mathematics 2009-10-31 Yuan-Pin Lee

We extend Donaldson's asymptotically holomorphic techniques to symplectic orbifolds. More precisely, given a symplectic orbifold such that the symplectic form defines an integer cohomology class, we prove that there exist sections of large…

Symplectic Geometry · Mathematics 2022-02-21 Fabio Gironella , Vicente Muñoz , Zhengyi Zhou

We prove an Atiyah-Segal isomorphism for the higher $K$-theory of coherent sheaves on quotient Deligne-Mumford stacks over $\C$. As an application, we prove the Grothendieck-Riemann-Roch theorem for such stacks. This theorem establishes an…

Algebraic Geometry · Mathematics 2019-10-18 Amalendu Krishna , Bhamidi Sreedhar

In this paper we show some Lefschetz-type theorems for the effective cone of Hyperk\"ahler varieties. In particular we are able to show that the inclusion of any smooth ample divisor induces an isomorphism of effective cones. Moreover we…

Algebraic Geometry · Mathematics 2023-09-07 Jonas Baltes

We formulate and prove a generalization of Zariski-van Kampen theorem on the topological fundamental groups of smooth complex algebraic varieties. As an application, we prove a hyperplane section theorem of Lefschetz-Zariski-van Kampen type…

Algebraic Geometry · Mathematics 2009-06-08 Ichiro Shimada

We give applications of the higher Lefschetz theorems for foliations of [BH10], primarily involving Haefliger cohomology. These results show that the transverse structures of foliations carry important topological and geometric information.…

Differential Geometry · Mathematics 2024-03-01 Moulay Tahar Benameur , James L. Heitsch

We prove the following results for toric Deligne-Mumford stacks, under minimal compactness hypotheses: the Localization Theorem in equivariant K-theory; the equivariant Hirzebruch-Riemann-Roch theorem; the Fourier--Mukai transformation…

Algebraic Geometry · Mathematics 2018-08-02 Tom Coates , Hiroshi Iritani , Yunfeng Jiang , Ed Segal

This paper proves a result on the existence of finite flat scheme covers of Deligne-Mumford stacks. This result is used to prove that a large class of smooth Deligne-Mumford stacks with affine moduli space are quotient stacks, and in the…

Algebraic Geometry · Mathematics 2016-09-07 Andrew Kresch , Angelo Vistoli

In this note, we obtain a number of results related to the hard Lefschetz theorem for pseudoeffective line bundles, due to Demailly, Peternell and Schneider. Our first result states that the holomorphic sections produced by the theorem are…

Algebraic Geometry · Mathematics 2020-05-14 Xiaojun Wu

We develop the Lefschetz fixed-point theory for noncompact manifolds of bounded geometry and uniformly continuous maps. Specifically, we define the uniform Lefschetz class $\mathscr{L}(f)$ of a uniformly continuous map $f\colon M\to M$ of a…

Algebraic Topology · Mathematics 2025-12-12 Tsuyoshi Kato , Daisuke Kishimoto , Mitsunobu Tsutaya

We prove Lefschetz type theorems for cohomology groups and Picard groups of degeneracy loci for vector bundle maps. We also treat the case of antisymmetric maps.

Algebraic Geometry · Mathematics 2007-05-23 O. Debarre

We prove a new kind of homological stability theorem for automorphism groups of finitely-generated projective modules over Dedekind domains, which takes into account all possible stabilisation maps between these, rather than only…

Commutative Algebra · Mathematics 2024-05-14 Oscar Randal-Williams

Hypertoric varieties are determined by hyperplane arrangements. In this paper, we use stacky hyperplane arrangements to define the notion of hypertoric Deligne-Mumford stacks. Their orbifold Chow rings are computed. As an application, some…

Algebraic Geometry · Mathematics 2008-07-19 Yunfeng Jiang , Hsian-Hua Tseng

Let $n$ be a positive even integer and $d$ a positive integer . To every complete family $Z$ of n dimensional degree d hypersurfaces in the projective space with isolated A-D-E singularities we construct according to an idea of…

Algebraic Geometry · Mathematics 2013-05-17 Philippe Eyssidieux , Damien Mégy

We prove a homological stabilization theorem for Hurwitz spaces: moduli spaces of branched covers of the complex projective line. This has the following arithmetic consequence: let l>2 be prime and A a finite abelian l-group. Then there…

Number Theory · Mathematics 2015-12-03 Jordan S. Ellenberg , Akshay Venkatesh , Craig Westerland

The purpose of this paper is to develop a theory of $(\infty, 1)$-stacks, in the sense of Hirschowitz-Simpson's `Descent Pour Les n-Champs', using the language of quasi-category theory and the author's local Joyal model structure. The main…

Algebraic Geometry · Mathematics 2020-07-08 Nicholas Meadows

Let X be a locally compact space with a continuous proper action of a locally compact group G. Assuming that X satisfies a certain kind of duality in equivariant bivariant Kasparov theory, we can enrich the classical construction of…

K-Theory and Homology · Mathematics 2015-10-23 Heath Emerson , Ralf Meyer