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Related papers: Positivity of Segre-MacPherson classes

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We study a class of signomials whose positive support is the set of vertices of a simplex and which may have several negative support points in the simplex. Various groups of authors have provided an exact characterization for the global…

Combinatorics · Mathematics 2026-02-11 Gennadiy Averkov , Jonas Ellwanger , Thorsten Theobald , Timo de Wolff

To each affine variety $X$ and $m_1,\ldots,m_k\in \mathbb{C}$ such that no subset of the $m_i$ add to zero, we construct a variety which for $m_1,\ldots,m_k \in \mathbb{N}$ specializes to the closed $(m_1,\ldots,m_k)$-incidence stratum of…

Algebraic Geometry · Mathematics 2019-03-13 Hunter Spink , Dennis Tseng

The aim of this paper is twofold. First we prove a theorem of extension of sections of a coherent subquotient of a hermitian vector bundle on a complex analytic space with control of the norms, without any of the smoothness assumptions that…

Number Theory · Mathematics 2007-05-23 Hugues Randriam

This note is an addendum to the paper `Global pluripotential theory over a trivially valued field' by the present authors, in which we prove two results. Let $X$ be an irreducible projective variety over an algebraically closed field field…

Algebraic Geometry · Mathematics 2023-09-07 Sebastien Boucksom , Mattias Jonsson

Given a bundle gerbe on a compact smooth manifold or, more generally, on a compact \'etale Lie groupoid $M$, we show that the corresponding category of gerbe modules, if it is non-trivial, is equivalent to the category of finitely generated…

Algebraic Topology · Mathematics 2014-01-14 Christoph Schweigert , Christopher Tropp , Alessandro Valentino

In 2010, B. Rhoades proved that promotion together with the fake-degree polynomial associated with rectangular standard Young tableaux give an instance of the cyclic sieving phenomenon. We extend this result to all skew standard Young…

Combinatorics · Mathematics 2023-10-04 Per Alexandersson , Stephan Pfannerer , Martin Rubey , Joakim Uhlin

We generalize the Chern class relation for the transversal intersection of two nonsingular varieties to a relation for possibly singular varieties, under a 'splayedness' assumption. The relation is shown to hold for both the…

Algebraic Geometry · Mathematics 2019-08-15 Paolo Aluffi , Eleonore Faber

In the generality of a rigidly-compactly generated tensor triangulated category, we introduce semi-Bousfield classes in terms of the vanishing of the tensor product in positive degrees with respect to a fixed reasonable $t$-structure. We…

Category Theory · Mathematics 2026-05-29 Dolors Herbera , Michal Hrbek , Giovanna Le Gros

We show that the generating series of Euler characteristics of Hilbert schemes of points on any algebraic surface with at worst $A_n$-type singularities is described by the theta series determined by integer valued positive definite…

Algebraic Geometry · Mathematics 2013-12-23 Yukinobu Toda

This paper divides into two parts. Let $(X,\omega)$ be a compact Hermitian manifold. Firstly, if the Hermitian metric $\omega$ satisfies the assumption that $\partial\overline{\partial}\omega^k=0$ for all $k$, we generalize the volume of…

Differential Geometry · Mathematics 2017-11-20 Zhiwei Wang

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

Quadratic entry locus manifold of type $\delta$ $X\subset\mathbb P^N$ of dimension $n\geq 1$ are smooth projective varieties such that the locus described on $X$ by the points spanning secant lines passing through a general point of the…

Algebraic Geometry · Mathematics 2009-09-15 Francesco Russo

We introduce a countable collection of positivity classes for Hermitian symmetric functions on a complex manifold, and establish their basic properties. We study a related notion of stability. The first main result shows that, if the…

Complex Variables · Mathematics 2007-05-23 John P. D'Angelo , Dror Varolin

In this paper, we prove that a compact K\"ahler manifold $X$ with pseudo-effective (resp. singular positively curved) tangent bundle admits a smooth (resp. locally constant) rationally connected fibration $\phi \colon X \to Y$ onto a finite…

Algebraic Geometry · Mathematics 2025-02-04 Shin-ichi Matsumura , Chenghao Qing

Let q be a power of a prime integer p, and let X be a Hermitian variety of degree q+1 in the n-dimensional projective space. We count the number of rational normal curves that are tangent to X at distinct q+1 points with intersection…

Algebraic Geometry · Mathematics 2012-03-20 Ichiro Shimada

Given a positively graded commutative coherent ring A which is finitely generated as an A_0-algebra, a bijection between the tensor Serre subcategories of qgr A and the set of all subsets Y\subseteq Proj A of the form…

Algebraic Geometry · Mathematics 2007-05-23 Grigory Garkusha , Mike Prest

Let $X$ be a smooth variety over a finite field $\mathbb{F}_q$. Let $\ell$ be a rational prime number invertible in $\mathbb{F}_q$. For an $\ell$-adic sheaf $\mathcal{F}$ on $X$, we construct a cycle supported on the singular support of…

Algebraic Geometry · Mathematics 2026-04-06 Daichi Takeuchi

We use the non-proper Morse theory of Palais-Smale to investigate the topology of smooth closed subvarieties of complex semi-abelian varieties, and that of their infinite cyclic covers. As main applications, we obtain the finite generation…

Algebraic Topology · Mathematics 2018-06-12 Yongqiang Liu , Laurentiu Maxim , Botong Wang

We generalize the classical definition of effectively closed subshift to finitely generated groups. We study classical stability properties of this class and then extend this notion by allowing the usage of an oracle to the word problem of…

Group Theory · Mathematics 2019-04-26 Nathalie Aubrun , Sebastián Barbieri , Mathieu Sablik

Let $\mathcal{F}$ be a coherent sheaf on a complex variety $X$ that has a locally free resolution $E^{\bullet}$. In [19], the authors constructed a pseudomeromorphic current whose support is contained in $supp(E^{\bullet})$ that represents…

Algebraic Geometry · Mathematics 2024-10-17 Zhaobo Tom Han