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Related papers: A primer on Seshadri constants

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We compute Seshadri constants of a torus equivariant nef vector bundle on a projective space satisfying certain conditions. As an application, we compute Seshadri constants of tangent bundles on projective spaces. We also consider…

Algebraic Geometry · Mathematics 2021-05-11 Jyoti Dasgupta , Bivas Khan , Aditya Subramaniam

The purpose of this paper is to explicitly compute the Seshadri constants of all ample line bundles on fake projective planes. The proof relies on the theory of the Toledo invariant, and more precisely on its characterization of…

Complex Variables · Mathematics 2016-10-04 Luca F. Di Cerbo

We study Seshadri constants of certain ample vector bundles on projective varieties. Our main motivation is the following question: Under what conditions are the Seshadri constants of ample vector bundles at least 1 at all points of the…

Algebraic Geometry · Mathematics 2023-08-09 Indranil Biswas , Krishna Hanumanthu , Snehajit Misra

We study Seshadri constants of the canonical bundle on minimal surfaces of general type. First, we prove that if the Seshadri constant $\eps(K_X,x)$ is between 0 and 1, then it is of the form $(m-1)/m$ for some integer $m\ge 2$. Secondly,…

Algebraic Geometry · Mathematics 2008-01-22 Thomas Bauer , Tomasz Szemberg

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

We study a Seshadri constant at a general point on a rational surface whose anticanonical linear system contains a pencil. First, we describe a Seshadri constant of an ample line bundle on such a rational surface explicitly by the numerical…

Algebraic Geometry · Mathematics 2013-07-16 Taro Sano

Let $Y$ be a submanifold of dimension $y$ of a polarized complex manifold $(X,A)$ of dimension $k\geq 3$, with $1\leq y\leq k-1$. We define and study two positivity conditions on $Y$ in $(X,A)$, called Seshadri $A$-bigness and (a stronger…

Algebraic Geometry · Mathematics 2011-09-23 Lucian Badescu , Mauro C. Beltrametti

We prove an analogue in higher dimensions of the classical Narasimhan-Seshadri theorem for strongly stable vector bundles of degree 0 on a smooth projective variety $X$ with a fixed ample line bundle $\Theta$. As applications, over fields…

Algebraic Geometry · Mathematics 2014-02-26 V. Balaji , A. J. Parameswaran

Working over C, we show that, apart possibly from a unique limit point, the possible values of multi-point Seshadri constant for general points on smooth projective surfaces form a discrete set. In addition to its theoretical interest, this…

Algebraic Geometry · Mathematics 2007-09-26 Brian Harbourne , Joaquim Roe

Let $X$ be a surface and let $L$ be an ample line bundle on $X$. We first obtain a lower bound for the Seshadri constant $\varepsilon(X,L,r)$, when $r \ge 3$. We then assume that $X$ is a ruled surface and study Seshadri constants on $X$ in…

Algebraic Geometry · Mathematics 2017-01-25 Krishna Hanumanthu , Alapan Mukhopadhyay

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

Okounkov bodies, which are closed convex sets defined for big line bundles, have rich information on the line bundles. On the other hand, Seshadri constants are invariants which measure the positivity of line bundles. In this paper, we…

Algebraic Geometry · Mathematics 2013-06-03 Atsushi Ito

Let $X$ be a projective surface and let $L$ be an ample line bundle on $X$. The global Seshadri constant $\varepsilon(L)$ of $L$ is defined as the infimum of Seshadri constants $\varepsilon(L,x)$ as $x\in X$ varies. It is an interesting…

Algebraic Geometry · Mathematics 2020-02-21 Łucja Farnik , Krishna Hanumanthu , Jack Huizenga , David Schmitz , Tomasz Szemberg

We give a method to estimate Seshadri constants on toric varieties at any point. By using the estimations and toric degenerations, we can obtain some new computations or estimations of Seshadri constants on non-toric varieties. In…

Algebraic Geometry · Mathematics 2013-02-01 Atsushi Ito

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

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

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

Based on the work of Okounkov, Kaveh-Khovanskii and Lazarsfeld-Mustata independently associated a convex body, called the Okounkov body, to a big divisor on a normal projective variety with respect to an admissible flag. Although the…

Algebraic Geometry · Mathematics 2018-06-26 Jaesun Shin

In this note we relate the SHGH Conjecture to the rationality of one-point Seshadri constants on blow ups of the projective plane, and explain how rationality of Seshadri constants can be tested with the help of functions on…

Algebraic Geometry · Mathematics 2013-04-02 Marcin Dumnicki , Alex Küronya , Catriona Maclean , Tomasz Szemberg