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Related papers: Seshadri constants via toric degenerations

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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 semi-stable degenerations of toric varieties determined by certain partitions of their moment polytopes. Analyzing their defining equations we prove a property of uniqueness.

Algebraic Geometry · Mathematics 2007-12-21 Marina Marchisio , Vittorio Perduca

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 apply the theory of Seshadri stratifications to embedded toric varieties $X_P\subseteq \mathbb P(V)$ associated with a normal lattice polytope $P$. The approach presented here is purely combinatorial and completely independent of…

Algebraic Geometry · Mathematics 2025-05-06 Rocco Chirivì , Martina Costa Cesari , Xin Fang , Peter Littelmann

Let $X$ be a smooth projective surface with Picard number 1. Let $L$ be the ample generator of the N\'eron-Severi group of $X$. Given an integer $r\ge 2$, we prove lower bounds for the Seshadri constant of $L$ at $r$ general points in $X$.

Algebraic Geometry · Mathematics 2016-10-20 Krishna Hanumanthu

We give the lower bound on Seshadri constants for the case of very ample line bundles on threefolds. We consider the situation when the Seshadri constant is strictly less than 2 and give a version of Bauer's theorem \cite[Theorem 2.1]{B1}…

Algebraic Geometry · Mathematics 2008-12-16 Kungho Chan

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 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 provide a construction of examples of semistable degeneration via toric geometry. The applications include a higher dimensional generalization of classical degeneration of K3 surface into 4 rational components, an algebraic geometric…

Algebraic Geometry · Mathematics 2007-05-23 Shengda Hu

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

We classify all 1-nodal degenerations of smooth Fano threefolds with Picard number 1 (both nonfactorial and factorial) and describe their geometry. In particular, we describe a relation between such degenerations and smooth Fano threefolds…

Algebraic Geometry · Mathematics 2024-11-14 Alexander Kuznetsov , Yuri Prokhorov

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

One of Demailly's characterizations of Seshadri constants on ample line bundles works with Lelong numbers of certain positive singular hermitian metrics. In this note sections of multiples of the line bundle are used to produce such metrics…

Algebraic Geometry · Mathematics 2007-05-23 Thomas Eckl

In the present paper we are concerned with the possible values of Seshadri constants. While in general every positive rational number appears as the local Seshadri constant of some ample line bundle, we point out that for adjoint line…

Algebraic Geometry · Mathematics 2010-11-23 Thomas Bauer , Tomasz Szemberg

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

In this note we contribute to the study of Seshadri constants on abelian and bielliptic surfaces. We specifically focus on bounds that hold on all such surfaces, depending only on the self-intersection of the ample line bundle under…

Algebraic Geometry · Mathematics 2020-08-19 Thomas Bauer , Łucja Farnik

In this article we compute Seshadri constants of ample line bundles on the blowup of Hirzebruch surface $\mathbb{F}_e$ at $r\leqslant e+3$ very general points. Similarly, we compute Seshadri constants on the blowups of certain decomposable…

Algebraic Geometry · Mathematics 2025-01-10 Cyril J. Jacob , Bivas Khan , Ronnie Sebastian

For fixed degree $d\leq 12$, we study the Hilbert scheme of degree $d$ smooth Fano threefolds in their anticanonical embeddings. We use this to classify all possible degenerations of these varieties to toric Fano varieties with at most…

Algebraic Geometry · Mathematics 2019-11-26 Jan Arthur Christophersen , Nathan Owen Ilten

We develop a new approach towards obtaining lower bounds of the Seshadri constants of ample adjoint divisors on smooth projective varieties $X$ in arbitrary characteristic. Let $x\in X$ be a closed point and $A$ an ample divisor on $X$. If…

Algebraic Geometry · Mathematics 2026-01-27 Linus Rösler

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