English
Related papers

Related papers: On Seshadri constants and point-curve configuratio…

200 papers

So far, Seshadri constants on abelian surfaces are completely understood only in the cases of Picard number one and on principally polarized abelian surfaces with real multiplication. Beyond that, there are partial results for products of…

Algebraic Geometry · Mathematics 2022-04-14 Maximilian Schmidt

Motivated by a similar result of Dumnicki, K\"uronya, Maclean and Szemberg under a slightly stronger hypothesis, we exhibit irrational single-point Seshadri constants on a rational surface $X$ obtained by blowing up very general points of…

Algebraic Geometry · Mathematics 2017-12-18 Krishna Hanumanthu , Brian Harbourne

In this paper we will propose a new method to investigate Seshadri constants, namely by means of (nested) Hilbert schemes. This will allow us to use the geometry of the latter spaces, for example the computations of the nef cone via…

Algebraic Geometry · Mathematics 2024-09-17 Jonas Baltes

The purpose of this paper is to study Seshadri constants on the self-product $E\times E$ of an elliptic curve $E$. We provide explicit formulas for computing the Seshadri constants of all ample line bundles on the surfaces considered. As an…

Algebraic Geometry · Mathematics 2008-06-30 Thomas Bauer , Christoph Schulz

We study the Seshadri constants of cyclic coverings of smooth surfaces. The existence of an automorphism on these surfaces can be used to produce Seshadri exceptional curves. We give a bound for multiple Seshadri constants on cyclic…

Algebraic Geometry · Mathematics 2007-05-23 Luis Fuentes Garcia

In "Seshadri fibrations of algebraic surfaces" [arXiv:0709.2592v1] we showed that if the multiple point Seshadri constants of an ample line bundle on a smooth projective surface in very general points satisfy certain inequality then the…

Algebraic Geometry · Mathematics 2008-06-10 Wioletta Syzdek , Tomasz Szemberg

In this paper, we study a relation between Seshadri constants and degrees of defining polynomials. In particular, we compute the Seshadri constants on Fano varieties obtained as complete intersections in rational homogeneous spaces of…

Algebraic Geometry · Mathematics 2013-02-01 Atsushi Ito , Makoto Miura

We examine how the Seshadri constant of an ample line bundle at a very general point of an algebraic surface can carry important global geometric information about the surface. In particular, we obtain a numerical criterion for when a…

Algebraic Geometry · Mathematics 2007-05-23 Michael Nakamaye

Let $X$ be a smooth complex projective curve and let $E$ be a vector bundle on $X$ which is not semistable. We consider a flag bundle $\pi: \text{Fl}(E) \to X$ parametrizing certain flags of fibers of $E$. The dimensions of the successive…

Algebraic Geometry · Mathematics 2024-04-10 Krishna Hanumanthu , Jagadish Pine

Let $e,r \ge 0$ be integers and let $\mathbb{F}_e : = \mathbb{P}(\mathcal{O}_{\mathbb{P}^1} \oplus \mathcal{O}_{\mathbb{P}^1}(-e))$ denote the Hirzebruch surface with invariant $e$. We compute the Seshadri constants of an ample line bundle…

Algebraic Geometry · Mathematics 2024-10-28 Krishna Hanumanthu , Cyril J. Jacob , Suhas B. N. , Amit Kumar Singh

Starting with the pioneering work of Ein and Lazarsfeld restrictions on values of Seshadri constants on algebraic surfaces have been studied by many authors. In the present note we show how approximation involving continued fractions…

Algebraic Geometry · Mathematics 2017-06-29 Lucja Farnik , Tomasz Szemberg , Justyna Szpond , Halszka Tutaj-Gasinska

Let $E$ be a vector bundle of rank $n$ on $\mathbb{P}^1$. Fix a positive integer $d$. Let $\mathcal{Q}(E,d)$ denote the Quot scheme of torsion quotients of $E$ of degree $d$ and let $Gr(E,d)$ denote the Grassmann bundle that parametrizes…

Algebraic Geometry · Mathematics 2021-10-14 Chandranandan Gangopadhyay , Krishna Hanumanthu , Ronnie Sebastian

We define Seshadri constants for Higgs bundles on smooth projective varieties over algebraically closed fields of characteristic zero. This definition is inspired by and analogous to the notion of Seshadri constants for ordinary vector…

Algebraic Geometry · Mathematics 2026-05-26 Krishna Hanumanthu , Snehajit Misra , Nabanita Ray

We study families of curves covering a projective surface and give lower bounds on the self-intersection of the members of such families, improving results of Ein-Lazarsfeld and Xu. We apply the obtained inequalities to get new insights on…

Algebraic Geometry · Mathematics 2008-09-15 Andreas Leopold Knutsen , Wioletta Syzdek , Tomasz Szemberg

In this article, we give a description of the closed cone of curves of the projective bundle $\mathbb{P}(E)$ over a smooth projective variety $X$. Using duality, we then calculate the nef cone of divisors in $\mathbb{P}(E)$ over some…

Algebraic Geometry · Mathematics 2022-08-19 Snehajit Misra , Nabanita Ray

We develop a local positivity theory for movable curves on projective varieties similar to the classical Seshadri constants of nef divisors. We give analogues of the Seshadri ampleness criterion, of a characterization of the augmented base…

Algebraic Geometry · Mathematics 2018-09-10 Mihai Fulger

Seshadri constants on abelian surfaces are fully understood in the case of Picard number one. Little is known so far for simple abelian surfaces of higher Picard number. In this paper we investigate principally polarized abelian surfaces…

Algebraic Geometry · Mathematics 2025-04-09 Thomas Bauer , Maximilian Schmidt

Let $X$ be a complex projective variety, and let $E_{\ast}$ be a parabolic vector bundle on $X$. We introduce the notion of \textit{parabolic Seshadri constants} of $E_{\ast}$. It is shown that these constants are analogous to the classical…

Algebraic Geometry · Mathematics 2023-06-08 Indranil Biswas , Krishna Hanumanthu , Snehajit Misra , Nabanita Ray

Let $X$ be a smooth complex projective curve, and let $E$ be a vector bundle on $X$ which is not semistable. For a suitably chosen integer $r$, let $\text{Gr}(E)$ be the Grassmann bundle over $X$ that parametrizes the quotients of the…

Algebraic Geometry · Mathematics 2019-05-24 Indranil Biswas , Krishna Hanumanthu , D. S. Nagaraj , Peter E. Newstead

In analogy to the relation between symplectic packings and symplectic blow ups we show that multiple point Seshadri constants on projective complex surfaces can be calculated as the supremum of radii of multiple K\"ahler ball embeddings.

Algebraic Geometry · Mathematics 2016-09-13 Thomas Eckl