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We calculate the cohomology rings of a collection of seven dimensional manifolds supporting an S^3 x S^3-action with one dimensional orbit space. These manifolds are of interest to differential geometers studying non-negative and positive…

Differential Geometry · Mathematics 2008-12-08 Christine M. Escher , S. K. Ultman

We construct an explicit de Rham isomorphism relating the cohomology rings of Banagl's de Rham and spatial approach to intersection space cohomology for stratified pseudomanifolds with isolated singularities. Intersection space…

Algebraic Topology · Mathematics 2020-01-28 Franz Wilhelm Schlöder , J. Timo Essig

Numerical equivalence of algebraic cycles is defined abstractly by intersection numbers. Classically, for smooth complex proper toric varieties, the quotients by numerical equivalence with rational coefficients can be described…

Algebraic Geometry · Mathematics 2026-05-14 Ryota Mikami

We compute the local cohomology of vector fields on a manifold. In the smooth case this recovers the diagonal cohomology studied in work of Losik, Guillemin, Fuks and others. In the holomorphic case this cohomology has recently appeared in…

Differential Geometry · Mathematics 2024-05-09 Brian R Williams

Let X be a smooth projective curve over a field k of characteristic zero. The differential fundamental group of X is defined as the Tannakian dual to the category of vector bundles with (integrable) connections on X. This work investigates…

Algebraic Geometry · Mathematics 2025-03-26 Vo Quoc Bao , Phung Ho Hai , Dao Van Thinh

We describe a method for counting maps of curves of given genus (and variable moduli) to $\Bbb P^2$, essentially by splitting the $\Bbb P^2$ in two; then specialising to the case of genus 0 we show that the method of quantum cohomology may…

alg-geom · Mathematics 2008-02-03 Ziv Ran

Let G be a linear algebraic group over the field of real numbers R, and let Y be a right homogeneous space of G. We wish to find a real point of Y or to prove that Y has no real points. We describe a method to do that, implicitly using…

Algebraic Geometry · Mathematics 2021-07-09 Mikhail Borovoi

A fundamental step in the classification of finite-dimensional complex pointed Hopf algebras is the determination of all finite-dimensional Nichols algebras of braided vector spaces arising from groups. The most important class of braided…

Quantum Algebra · Mathematics 2007-05-24 Nicolas Andruskiewitsch , Matias Graña

Quantum homogeneous supervector bundles arising from the quantum general linear supergoup are studied. The space of holomorphic sections is promoted to a left exact covariant functor from a category of modules over a quantum parabolic…

Quantum Algebra · Mathematics 2007-05-23 R. B. Zhang

The resultant veriety in the space of systems of homogeneous polynomials of given degrees consists of such systems having non-trivial solutions. We calculate the integer cohomology groups of all spaces of non-resultant systems of…

K-Theory and Homology · Mathematics 2014-09-23 V. A. Vassiliev

We construct a modification of Vassiliev's method of calculating cohomology groups of spaces of nonsingular algebraic hypersurfaces. We use this modified method to calculate the real cohomology groups of the space of nonsingular plane…

Algebraic Topology · Mathematics 2007-05-23 A. Gorinov

We consider cohomology of diagrams of algebras by Beck's approach, using comonads. We then apply this theory to computing the cohomology of $\Psi$-rings. Our main result is that there is a spectral sequence connecting the cohomology of the…

K-Theory and Homology · Mathematics 2008-02-26 Michael Robinson

The purpose of this note is to find explicit representatives in deRham cohomology for the generators of the cohomology of the moduli space of parabolic bundles, analogous to the results of \cite{groupcoho} for the moduli space of vector…

Symplectic Geometry · Mathematics 2024-02-12 Lisa Jeffrey , Yukai Zhang

We survey decades of research identifying the (co)homology of configuration spaces with Lie algebra (co)homology. The different routes to this one proto-theorem offer genuinely different explanations of its truth, and we attempt to convey…

Algebraic Topology · Mathematics 2025-08-21 Ben Knudsen

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

We compute the integer cohomology rings of the ``polygon spaces'' introduced in [Hausmann,Klyachko,Kapovich-Millson]. This is done by embedding them in certain toric varieties; the restriction map on cohomology is surjective and we…

dg-ga · Mathematics 2008-02-03 Jean-Claude Hausmann , Allen Knutson

Here we survey several results and conjectures on the cohomology of the total space of the Hitchin system: the moduli space of semi-stable rank n and degree d Higgs bundles on a complex algebraic curve C. The picture emerging is a dynamic…

Algebraic Geometry · Mathematics 2011-09-13 Tamas Hausel

We prove that cohomology and base change holds for algebraic stacks, generalizing work of Brochard in the tame case. We also show that Hom-spaces on algebraic stacks are represented by abelian cones, generalizing results of Grothendieck,…

Algebraic Geometry · Mathematics 2013-03-18 Jack Hall

The moduli stack of representations of a quiver, or coherent sheaves on a proper curve, carries two structures on its cohomology: a Hall algebra and braided vertex coalgebra. We show that they are compatible, by developing a formulation of…

Algebraic Geometry · Mathematics 2021-10-28 Alexei Latyntsev

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