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In order to understand the structure of the cohomologies involved in the study of projectively equivariant quantizations, we introduce a notion of affine representation of a Lie algebra.We show how it is related to linear representations…

Differential Geometry · Mathematics 2007-05-23 Sarah Hansoul , Pierre B. A. Lecomte

The real singular cohomology ring of a homogeneous space $G/K$, interpreted as the real Borel equivariant cohomology $H^*_K(G)$, was historically the first computation of equivariant cohomology of any nontrivial connected group action.…

Algebraic Topology · Mathematics 2023-12-05 Jeffrey D. Carlson

We give a cohomological classification of vector bundles of rank $2$ on a smooth affine threefold over an algebraically closed field having characteristic unequal to $2$. As a consequence we deduce that cancellation holds for rank $2$…

Algebraic Geometry · Mathematics 2015-01-14 Aravind Asok , Jean Fasel

The aim of this paper is to compare the structure and the cohomology spaces of Lie algebras and induced $3$-Lie algebras.

Rings and Algebras · Mathematics 2013-12-31 J. Arnlind , A. Kitouni , A. Makhlouf , S. Silvestrov

We study the arithmetical ranks and the cohomological dimensions of an infinite class of Cohen-Macaulay varieties of minimal degree. Among these we find, on the one hand, infinitely many set-theoretic complete intersections, on the other…

Commutative Algebra · Mathematics 2008-02-06 Margherita Barile

We define and compute a cohomology of the space of Jacobi forms based on precise analogues of Zhu reduction formulas. A counterpart of the Bott-Segal theorem for the reduction cohomology of Jacobi forms on the torus is proven. It is shown…

Number Theory · Mathematics 2025-10-20 A. Zuevsky

We compute the cohomology groups of the spaces of colorings of cycles, i.e., of the prodsimplicial complexes Hom(C_m,K_n). We perform the computation first with Z_2, and then with integer coefficients. The main technical tool is to use…

Algebraic Topology · Mathematics 2007-05-23 Dmitry N. Kozlov

In this PhD thesis we will discuss some aspects in Commutative Algebra which have interactions with Algebraic Geometry, Representation Theory and Combinatorics. In particular, in the first chapter we will focus on understanding when certain…

Commutative Algebra · Mathematics 2011-05-30 Matteo Varbaro

The integral cohomology ring of the complement of an arrangement of linear subspaces of a finite dimensional complex projective space is determined by combinatorial data, i.e. the intersection poset and the dimension function.

Algebraic Topology · Mathematics 2007-05-23 Carsten Schultz

Let $\mathcal{T}$ be an arbitrary resolution graph and $(X, 0)$ a generic complex analytic normal surface singularity, and $\tilde{X}$ a generic resolution corresponding to it. Fix an effective integer cycle $Z$ supported on the exceptional…

Algebraic Geometry · Mathematics 2020-03-31 János Nagy

We give an explicit description of the Barr- and Diaconescu covers of the arithmetic site, which are relevant to cohomology. Further, we construct the arithmetic site as the commutative shadow of a non-commutative topological space.

Rings and Algebras · Mathematics 2017-02-15 Lieven Le Bruyn

We introduce the notion of Lie-Yamaguti algebra bundle, define its cohomology groups with coefficients in a representation and show that such bundles appeared naturally from geometric considerations in the work of M. Kikkawa, which…

Rings and Algebras · Mathematics 2025-05-15 Saikat Goswami , Goutam Mukherjee

We study locally free sheaves of rank two on the projective line over the integers, especially indecomposable ones. Subsequently we apply various concepts of Arakelov geometry to these sheaves. We compute for example the arithmetic Chern…

Algebraic Geometry · Mathematics 2014-08-13 Fabian Reede

Enumerative Geometry is concerned with the number of solutions to a structured system of polynomial equations, when the structure comes from geometry. Enumerative real algebraic geometry studies real solutions to such systems, particularly…

Algebraic Geometry · Mathematics 2007-05-23 Frank Sottile

The $L^p$-cohomology in degree 1 of Riemannian homogeneous spaces is computed. It turns out that reduced cohomology does not vanish exactly for spaces quasiisometric to negatively curved homogeneous spaces.

Differential Geometry · Mathematics 2012-07-25 Pierre Pansu

Computing the cohomology of the tensor product of two vector bundles is central in the study of their moduli spaces and in applications to representation theory, combinatorics and physics. These computations play a fundamental role in the…

Algebraic Geometry · Mathematics 2021-08-25 Izzet Coskun , Jack Huizenga , John Kopper

In this paper, we introduce discrete approximate circle bundles, a class of objects designed to serve as the data science analog of circle bundles from algebraic topology. We show that, under appropriate conditions, one can meaningfully and…

Algebraic Topology · Mathematics 2026-03-11 Brad Turow , Jose A. Perea

We show that the linear map defined by multiplication with a general bi-homogeneous form between two bi-graduated pieces of the first cohomology of a nonsingular quadric in the projective space is of maximal rank. This is the first non…

Algebraic Geometry · Mathematics 2010-06-29 Salvatore Giuffrida , Renato Maggioni , Riccardo Re

We show that the cohomology table of any coherent sheaf on projective space is a convergent--but possibly infinite--sum of positive real multiples of the cohomology tables of what we call supernatural sheaves.

Algebraic Geometry · Mathematics 2009-02-11 David Eisenbud , Frank-Olaf Schreyer

We observe a general structure theorem for quantum cohomology rings, a non-homogeneous version of the usual cohomology ring encoding information about (almost holomorphic) rational curves. An application is the rigorous computation of the…

alg-geom · Mathematics 2008-02-03 Bernd Siebert , Gang Tian