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We confirm the quasi-projective case of Saito's conjecture, namely that the cohomological characteristic classes defined by Abbes and Saito can be computed in terms of the characteristic cycles. We construct a cohomological characteristic…

Algebraic Geometry · Mathematics 2025-02-18 Enlin Yang , Yigeng Zhao

We present a functorial computation of the equivariant intersection cohomology of a hypertoric variety, and endow it with a natural ring structure. When the hyperplane arrangement associated with the hypertoric variety is unimodular, we…

Algebraic Geometry · Mathematics 2015-05-13 Tom Braden , Nicholas J. Proudfoot

We extend Donaldson's asymptotically holomorphic techniques to symplectic orbifolds. More precisely, given a symplectic orbifold such that the symplectic form defines an integer cohomology class, we prove that there exist sections of large…

Symplectic Geometry · Mathematics 2022-02-21 Fabio Gironella , Vicente Muñoz , Zhengyi Zhou

It is known that hermitean random matrix ensembles can be identified with symmetric coset spaces of Lie groups, or else with tangent spaces of the same. This results in a classification of random matrix ensembles as well as applications in…

Mathematical Physics · Physics 2009-11-13 Ulrika Magnea

We investigate space curves with large cohomology. To this end we introduce curves of subextremal type. This class includes all subextremal curves. Based on geometric and numerical characterizations of curves of subextremal type, we show…

Algebraic Geometry · Mathematics 2007-05-23 Nadia Chiarli , Silvio Greco , Uwe Nagel

Based on a Whitehead-type characterization of the sectional category we develop the notion of weak sectional category. This is a new lower bound of the sectional category, which is inspired by the notion of weak category in the sense of…

Algebraic Topology · Mathematics 2014-02-26 J. M. G. Calcines , L. Vandembroucq

The aim of this paper is to connect two important and apparently unrelated theories: motivic homotopy theory and ramification theory. We construct motivic homotopy categories over a qcqs base scheme $S$, in which cohomology theories with…

Algebraic Geometry · Mathematics 2025-04-04 Junnosuke Koizumi , Hiroyasu Miyazaki , Shuji Saito

We describe the main properties of the $RO(C_2\times \Sigma_2)$-graded cohomology ring of a point and apply the results to compute the subring of motivic classes given by the Bredon motivic cohomology of real numbers and to compute…

Algebraic Topology · Mathematics 2026-05-29 Bill Deng , Mircea Voineagu

We study a family of subrings, indexed by the natural numbers, of the mod-p cohomology of a finite group G. These subrings are based on a family of v_n-periodic complex oriented cohomology theories and are constructed as rings of…

Algebraic Topology · Mathematics 2015-02-23 David J. Green , John R. Hunton , Bjoern Schuster

A classical result of A. Connes asserts that the Frechet algebra of smooth functions on a smooth compact manifold X provides, by a purely algebraic procedure, the de Rham cohomology of X. Namely the procedure uses Hochschild and cyclic…

alg-geom · Mathematics 2008-02-03 Jean-Paul Brasselet , André Legrand

This note is devoted to the study of the homology class of a compact Poisson transversal in a Poisson manifold. For specific classes of Poisson structures, such as unimodular Poisson structures and Poisson manifolds with closed leaves, we…

Symplectic Geometry · Mathematics 2017-04-18 Pedro Frejlich , Ioan Marcut

We construct an algebraic-cycle based model for the motivic cohomology on the category of schemes of finite type over a field, where schemes may admit arbitrary singularities and may be non-reduced. We show that our theory is functorial on…

Algebraic Geometry · Mathematics 2021-12-30 Jinhyun Park

We perform Hochschild homology calculations in the algebro-geometric setting of motives. The motivic Hochschild homology coefficient ring contains torsion classes which arise from the mod-$p$ motivic Steenrod algebra and from generating…

Algebraic Geometry · Mathematics 2022-04-04 Bjørn Ian Dundas , Michael A. Hill , Kyle Ormsby , Paul Arne Østvær

There are characteristic classes that are the obstructions to the vanishing of the differentials in the Lyndon-Hochischild-Serre spectral sequence of an extension of an integral lattice L by a group G. These characteristic classes exist in…

Algebraic Topology · Mathematics 2009-06-18 Nansen Petrosyan

Let $X_{\Sigma}$ be a smooth complete toric variety defined by a fan $\Sigma$ and let $V=V(I)$ be a subscheme of $X_{\Sigma}$ defined by an ideal $I$ homogeneous with respect to the grading on the total coordinate ring of $X_{\Sigma}$. We…

Algebraic Geometry · Mathematics 2017-11-15 Martin Helmer

In this paper, our aim is to find the relations amongst the cohomology classes of Brill-Noether subvarieties of the moduli space of semistable bundles over an elliptic curve. We obtain results similar to the Poincar\'e relations on a…

Algebraic Geometry · Mathematics 2019-11-12 Arijit Mukherjee

We explicitly construct a symplectomorphism that relates magnetic twists to the invariant hyperk\"ahler structure of the tangent bundle of a Hermitian symmetric space. This symplectomorphism reveals foliations by (pseudo-) holomorphic…

Symplectic Geometry · Mathematics 2024-06-25 Johanna Bimmermann

It is shown that the characteristic classes of foliations that were defined by Losik and that take values in the de~Rham cohomology of the space of infinite order frames over the leaf space may be mapped to the characteristic classes with…

Differential Geometry · Mathematics 2019-12-05 Anton S. Galaev

We study some properties of quadratic forms with values in a field whose underlying vector spaces are endowed with the structure of right vector spaces over a division ring extension of that field. Some generalized notions of isotropy,…

Rings and Algebras · Mathematics 2019-06-18 Amir Hossein Nokhodkar

The object of this article is to compute the holonomy group of the normal connection of complex parallel submanifolds of the complex projective space. We also give a new proof of the classification of complex parallel submanifolds by using…

Differential Geometry · Mathematics 2007-05-23 Antonio J. Di Scala , Sergio Console
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