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We prove that Schubert and Richardson varieties in flag manifolds are uniquely determined by their equivariant cohomology classes, as well as a stronger result that replaces Schubert varieties with closures of Bialynicki-Birula cells under…

Algebraic Geometry · Mathematics 2025-08-27 Anders S. Buch , Pierre-Emmanuel Chaput , Nicolas Perrin

We consider closed manifolds that admit a metric locally isometric to a product of symmetric planes. For such manifolds, we prove that the Euler characteristic is an obstruction to the existence of flat structures, confirming an old…

Geometric Topology · Mathematics 2009-05-23 Michelle Bucher , Tsachik Gelander

We bound the second Chern class of the tangent sheaf of a codimension-one foliation. Equivalently, we bound the degree of the pure codimension-two part of the singular scheme. In particular, for a degree-$d$ foliation on the projective…

Algebraic Geometry · Mathematics 2026-01-21 Alan Muniz

We show that whenever a closed symplectic manifold admits a Hamiltonian diffeomorphism with finitely many simple periodic orbits, the manifold has a spherical homology class of degree two with positive symplectic area and positive integral…

Symplectic Geometry · Mathematics 2016-11-15 Viktor L. Ginzburg , Basak Z. Gurel

The goal of this paper is to study the Chern classes of coherent sheaves (and more generally perfect complexes) that admit crystal structures in the setting of crystalline cohomology and more generally relative prismatic cohomology. In the…

Algebraic Geometry · Mathematics 2023-10-03 Bhargav Bhatt

In this thesis I lift the Curry--Howard--Lambek correspondence between the simply-typed lambda calculus and cartesian closed categories to the bicategorical setting, then use the resulting type theory to prove a coherence result for…

Category Theory · Mathematics 2020-07-02 Philip Saville

We give a Chern-Weil map for the Gel'fand-Fuks characteristic classes of Haefliger-singular foliations, those foliations defined by smooth Haefliger structures with dense regular set. Our characteristic map constructs, out of singular…

Differential Geometry · Mathematics 2025-03-19 Lachlan Ewen MacDonald , Benjamin McMillan

Michael Gromov has recently initiated what he calls ``symbolic algebraic geometry", in which objects are proalgebraic varieties: a proalgebraic variety is by definition the projective limit of a projective system of algebraic varieties. In…

Algebraic Geometry · Mathematics 2013-06-21 Shoji Yokura

We first construct closed spherical CR manifolds of dimension at least five having non-trivial first Chern class with real coefficients. We next prove a constraint on Chern classes with real coefficients of (not necessarily closed)…

Differential Geometry · Mathematics 2022-10-13 Yuya Takeuchi

We introduce a notion of integration on the category of proper birational maps to a given variety $X$, with value in an associated Chow group. Applications include new birational invariants; comparison results for Chern classes and numbers…

Algebraic Geometry · Mathematics 2012-04-10 Paolo Aluffi

In this article, we prove the orbifold version of the Bogomolov-Gieseker inequality for stable $\mathbb Q$-sheaves on K\"ahler varieties, generalizing our earlier work \cite{GP25} in dimension three. We also provide a characterization of…

Algebraic Geometry · Mathematics 2026-01-14 Henri Guenancia , Mihai Păun

These notes form the next episode in a series of articles dedicated to a detailed proof of a cohomological index formula for transversally elliptic pseudo-differential operators and applications. The first two chapters are already available…

Differential Geometry · Mathematics 2008-01-21 Paul-Emile Paradan , Michèle Vergne

A survey of some results and open questions related to the following algebraic invariants of compact complex manifolds, that can be obtained from differential forms: cohomology groups, Chern classes, rational homotopy groups, and higher…

Algebraic Topology · Mathematics 2025-03-11 Jonas Stelzig

In this note we give a simple, model-independent construction of Chern classes as natural transformations from differential complex K-theory to differential integral cohomology. We verify the expected behaviour of these Chern classes with…

K-Theory and Homology · Mathematics 2009-07-16 Ulrich Bunke

A geometric construction of Sullivan's Stiefel-Whitney homology classes of a real analytic variety $X$ is given by means of the conormal cycle of an embedding of $X$ in a smooth variety. We prove that the Stiefel-Whitney classes define…

dg-ga · Mathematics 2008-02-03 Joseph H. G. Fu , Clint McCrory

In this note we prove a conjecture of Kashiwara, which states that the Euler class of a coherent analytic sheaf F on a complex manifold X is the product of the Chern character of F with the Todd class of X. As a corollary, we obtain a…

Algebraic Geometry · Mathematics 2017-10-10 Julien Grivaux

Let $G$ be a connected affine algebraic group and $X$ a regular $G$-variety (in the sense of Bifet-De Concini-Procesi) with open orbit $G/H$ and boundary divisor $D$. We show the vanishing of the $G$-equivariant Chern classes of the bundle…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion , Ivan Kausz

In this paper, we introduce six axioms for relative Bott-Chern secondary characteristic classes and prove the uniqueness and existence theorem for them. Such a work provides us a natural way to understand and hence to prove the arithmetic…

Algebraic Geometry · Mathematics 2007-05-23 Lin Weng

Let $f:X\to Y$ be a projective birational morphism, between complex quasi-projective varieties. Fix a bivariant class $\theta \in H^0(X\stackrel{f}\to Y)\cong Hom_{D^{b}_{c}(Y)}(Rf_*\mathbb A_X, \mathbb A_Y)$ (here $\mathbb A$ is a…

Algebraic Geometry · Mathematics 2021-09-07 Vincenzo Di Gennaro , Davide Franco , Carmine Sessa

We obtain refined generating series formulae for equivariant characteristic classes of external and symmetric products of singular complex quasi-projective varieties. More concretely, we study equivariant versions of Todd, Chern and…

Algebraic Geometry · Mathematics 2018-03-16 Laurentiu Maxim , Joerg Schuermann