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This paper investigates the representation-theoretic structure of the Koszul cohomology of a smooth projective variety $X$ over an algebraically closed field $k$, admitting an action of a finite group $G$ of order coprime to ${\rm…

Algebraic Geometry · Mathematics 2026-02-19 Kostas Karagiannis , Aristides Kontogeorgis , Konstantia Manousou Sotiropoulou

In the appendix of the famous book "Commutative Algebra with a View Towards Algebraic Geometry" one can find an infinite family of complexes indexed by integers. This family includes Eagon-Northcott and Buschsbaum-Rim complexes. The…

Commutative Algebra · Mathematics 2014-12-19 Mikhail Gudim

The article is devoted to a comparison of the \v{C}ech cohomology with the coefficients in a presheaf of Abelian groups and the topos cohomology of the sheaf generated by this presheaf for a poset with the Aleksandrov topology. The article…

Algebraic Topology · Mathematics 2026-02-19 Ahmet A. Husainov

In this survey, we discuss whether the complex projective space can be characterized by its integral cohomology ring among compact complex manifolds.

Algebraic Geometry · Mathematics 2015-12-15 Olivier Debarre

We show that the total cohomology of the canonical bundle of a smooth projective variety, seen as a module over an exterior algebra, splits into a natural direct sum of submodules which are generated in degree zero and have a linear free…

Algebraic Geometry · Mathematics 2011-05-06 Robert Lazarsfeld , Mihnea Popa , Christian Schnell

Linearized Legendrian contact homology (LCH) and bilinearized LCH are important homological invariants for Legendrian submanifolds in contact geometry. For legendrian knots in $\mathbb{R}^3$, very little was previously known about the…

Symplectic Geometry · Mathematics 2025-10-28 Frédéric Bourgeois , Salammbo Connolly

The present paper is a continuation of our work on curved finitary spacetime sheaves of incidence algebras and treats the latter along Cech cohomological lines. In particular, we entertain the possibility of constructing a non-trivial de…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. Mallios , I. Raptis

We compute the Poisson cohomology associated with several three dimensional Lie algebras. Together with existing results and the classification of three dimensional Lie algebras, this provides the Poisson cohomology of all linear Poisson…

Symplectic Geometry · Mathematics 2023-09-18 Douwe Hoekstra , Florian Zeiser

We study normal compact K\"ahler spaces whose rational cohomology ring is isomorphic to that of a complex torus. We call them rational cohomology tori. We classify, up to dimension three, those with rational singularities. We then give…

Algebraic Geometry · Mathematics 2017-03-29 Olivier Debarre , Zhi Jiang , Martí Lahoz , William F. Sawin

v2: We improved a little bit according to the referee's wishes. v1: On $X$ projective smooth over a field $k$, Pink and Roessler conjecture that the dimension of the Hodge cohomology of an invertible $n$-torsion sheaf $L$ is the same as the…

Algebraic Geometry · Mathematics 2008-02-28 Hélène Esnault , Arthur Ogus

We describe the cohomological Hall algebra of torsion sheaves on a weighted projective line with weights $(2, \dots, 2)$ in terms of generators and relations.

Algebraic Geometry · Mathematics 2025-02-24 Timm Peerenboom

We prove a generic flatness result for the cohomology of thickenings of a projective scheme that is smooth over a Noetherian domain containing a field of characteristic zero. Our study is motivated, in part, by a classical question in…

Algebraic Geometry · Mathematics 2026-03-06 Edoardo Ballico , Yairon Cid-Ruiz , Anurag K. Singh

Let $\Omega$ be a tiling space and let $G$ be the maximal group of rotations which fixes $\Omega$. Then the cohomology of $\Omega$ and $\Omega/G$ are both invariants which give useful geometric information about the tilings in $\Omega$. The…

Operator Algebras · Mathematics 2015-06-17 Charles Starling

In this paper we construct Cech cohomology groups that form a Gysin-type long exact sequence for principal torus bundles. This sequence is modeled on a de Rham cohomology sequence published in earlier work by Bouwknegt, Hannabuss and…

Geometric Topology · Mathematics 2011-09-28 Peter Bouwknegt , Rshni Ratnam

A product of cochains in a polyhedral complex is constructed. The multiplication algorithm depends on the choice of a parameter. The parameter is a linear functional on the ambient space. Cocycles form a subring of the ring of cochains,…

Algebraic Topology · Mathematics 2015-08-14 B. Kazarnovskii

A famous problem in discrete geometry is to find all monohedral plane tilers, which is still open to the best of our knowledge. This paper concerns with one of its variants that to determine all convex polyhedra whose every cross-section…

Combinatorics · Mathematics 2012-10-23 David G. L. Wang

Atiyah and Hirzebruch gave examples ofeven degree torsion classes in the singularcohomology of a smooth complex projective manifold, which arenot Poincar\'{e} dual to an algebraiccycle. We notice that the order ofthese classes are small…

Algebraic Geometry · Mathematics 2007-05-23 C. Soule , C. Voisin

A lot of good properties of etale cohomology only hold for torsion coefficients. We use "enlargement of categories" as developed in http://arxiv.org/abs/math.CT/0408177 to define a cohomology theory that inherits the important properties of…

Algebraic Geometry · Mathematics 2007-05-23 Lars Brünjes , Christian Serpé

Building on the recent computation of the cohomology rings of smooth toric varieties and partial quotients of moment-angle complexes, we investigate the naturality properties of the resulting isomorphism between the cohomology of such a…

Algebraic Topology · Mathematics 2025-07-04 Matthias Franz , Xin Fu

We construct an associative ring which is a deformation of the quantum cohomology ring of the projective plane. Just as the quantum cohomology encodes the incidence characteristic numbers of rational plane curves, the contact cohomology…

alg-geom · Mathematics 2016-08-15 Lars Ernström , Gary Kennedy