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Related papers: Some general \'etale Weak Lefschetz-type theorems

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We give an overview of recent developments around a characteristic class version of the Hodge index theorem for singular complex algebraic varieties. This was formulated by Brasselet-Schuermann-Yokura as a conjecture expressing the…

Algebraic Geometry · Mathematics 2025-11-13 Mohammadali Aligholi , Laurentiu Maxim , Joerg Schuermann

Let $A$ be an excellent two-dimensional normal local ring containing an algebraically closed field and let $X\to \mathrm{Spec} (A)$ be a resolution of singularity. We prove a theorem giving a condition under which the dimension of the…

Algebraic Geometry · Mathematics 2025-12-16 Tomohiro Okuma , Kei-ichi Watanabe , Ken-ichi Yoshida

This paper gives a uniform-theoretic refinement of classical homotopy theory. Both cubical sets (with connections) and uniform spaces admit classes of weak equivalences, special cases of classical weak equivalences, appropriate for the…

Algebraic Topology · Mathematics 2021-09-20 Sanjeevi Krishnan , Crichton Ogle

We provide new families of compact complex manifolds with no K\"ahler structure carrying symplectic structures satisfying the \textit{Hard Lefschetz Condition}. These examples are obtained as compact quotients of the solvable Lie group…

Differential Geometry · Mathematics 2025-09-26 Francesca Lusetti , Adriano Tomassini

Let $k$ be an algebraically closed field of characteristic not equal to 2 or 3, let $G$ be an almost simple algebraic group of type $F_4$, $G_2$ or $D_4$ and let $\theta$ be an automorphism of $G$ of finite order, coprime to the…

Rings and Algebras · Mathematics 2010-05-12 Paul Levy

Complex supermanifold structures being deformations of the exterior algebra of a holomorphic vector bundle, have been parametrized by orbits of a group on non-abelian cohomology by P. Green. For the case of odd dimension $4$ and $5$ an…

Complex Variables · Mathematics 2016-01-28 Matthias Kalus

In this paper, we prove the integrality conjecture for quotient stacks arising from weakly symmetric representations of reductive groups. Our main result is a decomposition of the cohomology of the stack into finite-dimensional components…

Representation Theory · Mathematics 2026-01-21 Lucien Hennecart

In this short paper, we give a $p$-adic analogue of the Hard Leftschetz Theorem.

Algebraic Geometry · Mathematics 2015-01-30 Daniel Caro

In this paper we use invariant theory to develop the notion of cohomological detection for Type I classical Lie superalgebras. In particular we show that the cohomology with coefficients in an arbitrary module can be detected on smaller…

Representation Theory · Mathematics 2010-10-18 Gustav I. Lehrer , Daniel K. Nakano , Ruibin Zhang

If X is a complex projective variety with klt singularities, then the mixed Hodge structures on the first two singular cohomology groups are pure. We describe the pieces of the Hodge decomposition in terms of reflexive differential forms.…

Algebraic Geometry · Mathematics 2016-12-07 Martin Schwald

A new approach to prove weak convergence of random polytopes on the space of compact convex sets is presented. This is used to show that the profile of the rescaled Schl\"afli random cone of a random conical tessellation generated by $n$…

Probability · Mathematics 2023-06-22 Zakhar Kabluchko , Daniel Temesvari , Christoph Thäle

We explicitly describe cohomology of the sheaf of differential forms with poles along a semiample divisor on a complete simplicial toric variety. As an application, we obtain a new vanishing theorem which is an analogue of the…

Algebraic Geometry · Mathematics 2007-05-23 Anvar Mavlyutov

An important, if relatively less well known aspect of the singularity theorems in Lorentzian Geometry is to understand how their conclusions fare upon weakening or suppression of one or more of their hypotheses. Then, theorems with modified…

General Relativity and Quantum Cosmology · Physics 2014-08-20 I. P. Costa e Silva , J. L. Flores

We review the shape theory of $\infty$-topoi, and relate it with the usual cohomology of locally constant sheaves. Additionally, a new localization of profinite spaces is defined which allows us to extend the \'etale realization functor of…

Algebraic Topology · Mathematics 2017-08-15 Joe Berner

We construct and study some vertex theoretic invariants associated to Poisson varieties, specialising in the conformal weight $0$ case to the familiar package of Poisson homology and cohomology. In order to do this conceptually we sketch a…

Algebraic Geometry · Mathematics 2020-11-13 E. Bouaziz

In this paper, we study cohomology groups of vector bundles on neighborhoods of a non-pluriharmonic locus in Stein manifolds and in projective manifolds. By using our results, we show variants of the Lefschetz hyperplane theorem.

Complex Variables · Mathematics 2020-02-18 Yusaku Tiba

For each g > 2 and h > 1, we explicitly construct (1) fiber sum indecomposable relatively minimal genus g Lefschetz fibrations over genus h surfaces whose monodromies lie in the Torelli group, (2) fiber sum indecomposable genus g surface…

Geometric Topology · Mathematics 2012-10-31 R. Inanc Baykur , Dan Margalit

We study a variety of questions centered around the computation of cohomology of line bundles on the incidence correspondence (the partial flag variety parametrizing pairs consisting of a point in projective space and a hyperplane…

Algebraic Geometry · Mathematics 2024-11-21 Annet Kyomuhangi , Emanuela Marangone , Claudiu Raicu , Ethan Reed

We first give a relative flexible process to construct torsion cohomology classes for Shimura varieties of Kottwitz-Harris-Taylor type with coefficient in a non too regular local system. We then prove that associated to each torsion…

Number Theory · Mathematics 2017-01-03 Pascal Boyer

Let G be a compact, connected Lie group, acting smoothly on a manifold M. Goresky-Kottwitz-MacPherson described a small Cartan model for the equivariant cohomology of M, quasi-isomorphic to the standard Cartan complex of equivariant…

Differential Geometry · Mathematics 2007-07-26 A. Alekseev , E. Meinrenken