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Related papers: Seshadri constants on hyperelliptic surfaces

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In the present note, we focus on certain properties of special curves that might be used in the theory of multi-point Seshadri constants for ample line bundles on the complex projective plane. In particular, we provide three…

Algebraic Geometry · Mathematics 2023-01-10 Piotr Pokora

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 $e,r \ge 0$ 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

We define and study a version of Seshadri constant for ample line bundles in positive characteristic. We prove that lower bounds for this constant imply the global generation or very ampleness of the corresponding adjoint line bundle. As a…

Algebraic Geometry · Mathematics 2014-05-06 Mircea Mustata , Karl Schwede

The aim of this note is to study local and global Seshadri constants for a family of smooth surfaces with prescribed polarization. We shall first observe that given $\alpha$ being smaller than the square root of the degree of polarization,…

Algebraic Geometry · Mathematics 2007-05-23 Keiji Oguiso

We prove that classes of rational curves on very general Enriques surfaces are always $2$-divisible. As a consequence, we prove that the Seshadri constant of any big and nef line bundle on a very general Enriques surface coincides with the…

Algebraic Geometry · Mathematics 2024-07-01 Concettina Galati , Andreas Leopold Knutsen

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

We give an asymptotic formula for the number of $\mathbb{F}_{q}$-rational points over a fixed determinant moduli space of stable vector bundles of rank $r$ and degree $d$ over a smooth, projective curve $X$ of genus $g \geq 2$ defined over…

Algebraic Geometry · Mathematics 2024-09-18 Arijit Dey , Sampa Dey , Anirban Mukhopadhyay

Let $X = \mathbb{P}(E_1) \times_C \mathbb{P}(E_2)$ where $C$ is a smooth curve and let $E_1$, $E_2$ be vector bundles over $C$. In this paper, we extend the results in \cite{K-M-R} by computing the nef cone of $X$ without restriction on the…

Algebraic Geometry · Mathematics 2020-03-03 Rupam Karmakar , Snehajit Misra

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

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

For a positive integer $n$, let $X_n \to X_{n-1} \to \ldots \to X_2 \to X_1 \to X_0$ be a Bott tower of height $n$, and let $L$ be a nef line bundle on $X_n$. We compute Seshadri constants $\varepsilon(X_n,L,x)$ of $L$ at any point $x \in…

Algebraic Geometry · Mathematics 2022-03-14 Indranil Biswas , Jyoti Dasgupta , Krishna Hanumanthu , Bivas Khan

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

We prove that the Seshadri constant of a polarized abelian variety is equal to the Seshadri constant of its abelian subvariety if the Seshadri constant is relatively small with respect to its degree, or it contains an abelian divisor which…

Algebraic Geometry · Mathematics 2022-05-27 Rikito Ohta

We introduce Seshadri constants for line bundles in a relative setting. They generalize the classical Seshadri constants of line bundles on projective varieties and their extension to vector bundles studied by Beltrametti-Schneider-Sommese…

Algebraic Geometry · Mathematics 2019-03-06 Mihai Fulger , Takumi Murayama

We compute in this note the Seshadri constants of the anticanonical bundle at every point of Del Pezzo surfaces. During the proof, we enlight the role of rational curves in our computations. We present then two exemples where the positivity…

Algebraic Geometry · Mathematics 2007-05-23 Amaël Broustet

In the paper we present an alternative approach to the boundedness of Seshadri constants (which measure the local positivity) of nef and big line bundles at a general point of a complex--projective variety. Our approach is based on the…

alg-geom · Mathematics 2008-02-03 Oliver Küchle , Andreas Steffens

We give a lower bound of the $\delta$-invariants of ample line bundles in terms of Seshadri constants. As applications, we prove the uniform K-stability of infinitely many families of Fano hypersurfaces of arbitrarily large index, as well…

Algebraic Geometry · Mathematics 2022-04-28 Hamid Abban , Ziquan Zhuang

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

The main goal of this paper is to present a new algorithm bounding the regularity and ``alpha'' (the lowest degree of existing hypersurface) of a linear system of hypersurfaces (in $\mathbb P^n$) passing through multiple points in general…

Algebraic Geometry · Mathematics 2008-02-08 Marcin Dumnicki