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We describe the cohomology groups of a homogeneous vector bundle $E$ on any Hermitian symmetric variety $X=G/P$ of ADE type as the cohomology of a complex explicitly described. The main tool is the equivalence between the category of…

Algebraic Geometry · Mathematics 2007-05-23 Giorgio Ottaviani , Elena Rubei

We examine the integral cohomology rings of certain families of $2n$-dimensional orbifolds $X$ that are equipped with a well-behaved action of the $n$-dimensional real torus. These orbifolds arise from two distinct but closely related…

Algebraic Topology · Mathematics 2018-03-16 Anthony Bahri , Soumen Sarkar , Jongbaek Song

We study the cohomology ring of the complement $\mathcal{M}(\mathcal{A})$ of a manifold arrangement $\mathcal{A}$ in a smooth manifold $M$ without boundary. We first give the concept of monoidal cosheaf on a locally geometric poset…

Algebraic Topology · Mathematics 2021-09-08 Junda Chen , Zhi Lü , Jie Wu

We determine the structure of the first resonance variety of the cohomology ring of the group of automorphisms of a finitely generated free group which act by conjugation on a given basis.

Group Theory · Mathematics 2009-06-11 Daniel C. Cohen

We compute the cohomology with group ring coefficients of the complement of a finite collection of affine hyperplanes in a finite dimensional complex vector space. It is nonzero in exactly one degree, namely the degree equal to the rank of…

Algebraic Topology · Mathematics 2010-02-23 Michael W Davis , Tadeusz Januszkiewicz , Ian J Leary , Boris Okun

In this paper we build an Orlik-Solomon model for the canonical gradation of the cohomology algebra with integer coefficients of the complement of a toric arrangement. We give some results on the uniqueness of the representation of…

Algebraic Topology · Mathematics 2020-07-20 Roberto Pagaria

This is the second in a sequence of three articles exploring the relationship between commutative algebras and $E_\infty$-algebras in characteristic $p$ and mixed characteristic. Given a topological space $X,$ we construct, in a manner…

Algebraic Topology · Mathematics 2025-01-20 Oisín Flynn-Connolly

Let $K$ be a field of characteristic zero, $R = K[X_1,\ldots,X_n]$. Let $A_n(K) = K<X_1,\ldots,X_n, \partial_1, \ldots, \partial_n>$ be the $n^{th}$ Weyl algebra over $K$. We consider the case when $R$ and $A_n(K)$ is graded by giving $\deg…

Commutative Algebra · Mathematics 2013-10-18 Tony J. Puthenpurakal , Rakesh B. T. Reddy

The focus of this paper is on a poorly understood invariant of a commutative noetherian local ring $R$ with residue field $k$: the stable cohomology modules $\hat{Ext}^{n}_R(k,k)$, defined for each $n\in\mathbb{Z}$ by Benson and Carlson,…

Commutative Algebra · Mathematics 2007-05-23 Luchezar L. Avramov , Oana Veliche

Let $X$ be a topological space. We consider certain generalized configuration spaces of points on $X$, obtained from the cartesian product $X^n$ by removing some intersections of diagonals. We give a systematic framework for studying the…

Algebraic Topology · Mathematics 2020-02-19 Dan Petersen

This paper is the first in a series that describe a conjectural analog of the geometric Satake isomorphism for an affine Kac-Moody group. In this paper we construct a model for the singularities of some would-be Schubert varieties in the…

Algebraic Geometry · Mathematics 2019-12-19 Alexander Braverman , Michael Finkelberg

Let A be a (central) arrangement of hyperplanes in a finite dimension complex vector space V. Let M(A) be the dependence matroid determined by A. The Orlik-Solomon algebra OS(M) of a matroid M is the exterior algebra on the points modulo…

Combinatorics · Mathematics 2012-01-19 Raul Cordovil , David Forge

Cohomology support loci of rank one local systems of a smooth quasiprojective complex algebraic variety are finite unions of torsion-translated complex subtori of the character variety of the fundamental group. Tangent spaces of the…

Algebraic Geometry · Mathematics 2015-07-28 Nero Budur , Botong Wang , Youngho Yoon

We show by studying the symplectic geometry of the extended moduli space that the intersection cohomology of the representation space $Hom(\pi_1(\Sigma),G)/G$ for a simply connected compact Lie group $G$ is naturally embedded into the $G$…

Algebraic Geometry · Mathematics 2007-05-23 Young-Hoon Kiem

If the $\ell$-adic cohomology of a projective smooth variety, defined over a $\frak{p}$-adic field $K$ with finite residue field $k$, is supported in codimension $\ge 1$, then any model over the ring of integers of $K$ has a $k$-rational…

Number Theory · Mathematics 2007-05-23 Hélène Esnault

For the toric variety X associated to the Bruhat poset of Schubert varieties in the Grassmannian, we describe the singular locus in terms of the faces of the associated polyhedral cone. We also determine the tangent cones at the maximal…

Algebraic Geometry · Mathematics 2007-11-09 Justin A. Brown , V. Lakshmibai

Let X be an orthogonal Grassmannian parametrizing isotropic subspaces in an even dimensional vector space equipped with a nondegenerate symmetric form. We prove a Giambelli formula which expresses an arbitrary Schubert class in the singular…

Algebraic Geometry · Mathematics 2012-04-02 Anders S. Buch , Andrew Kresch , Harry Tamvakis

Local system cohomology groups of the complements of hyperplane arrangements have played an important role in the theory of hypergeometric integrals, the topology of Milnor fibers and covering spaces. One of the important theorems is the…

Geometric Topology · Mathematics 2023-04-24 Sakumi Sugawara

In Homotopy Type Theory, cohomology theories are studied synthetically using higher inductive types and univalence. This paper extends previous developments by providing the first fully mechanized definition of cohomology rings. These rings…

Algebraic Topology · Mathematics 2022-12-09 Thomas Lamiaux , Axel Ljungström , Anders Mörtberg

Let A be an arbitrary ring. We introduce a Dennis trace map mod n, from K_1(A;Z/n) to the Hochschild homology group with coefficients HH_1(A;Z/n). If A is the ring of integers in a number field, explicit elements of K_1(A,Z/n) are…

Number Theory · Mathematics 2009-10-31 Max Karoubi , Thierry Lambre