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Related papers: Remarks on Seshadri constants

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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 the hyperbolicity of the log variety $(\mathbb{P}^n, X)$, where $X$ is a very general hypersurface of degree $d\geq 2n+1$ (which is the bound predicted by the Kobayashi conjecture). Using a positivity result for the sheaf of…

Algebraic Geometry · Mathematics 2007-05-23 Gianluca Pacienza , Erwan Rousseau

For a line bundle L on a smooth surface S, it is now known that the degree of the Severi variety of cogenus-d curves is given by a universal polynomial in the Chern classes of L and S if L is d-very ample. For S rational, we relax the…

Algebraic Geometry · Mathematics 2013-02-08 Steven L. Kleiman , Vivek V. Shende , with an appendix by Ilya Tyomkin

Let $X$ be the moduli space of semistable rank 2 vector bundles over a smooth curve C of genus $g \ge 2$ and $\theta : X \to PH^0(L)^*$ be the map associated to the generalized theta divisor L on X. We prove that for C not hyperelliptic,…

alg-geom · Mathematics 2008-02-03 S. Brivio , A. Verra

Let $S$ and $T$ be reduced divisors on $\mathbb{P}^2$ which have no common components, and $\Delta=S+2\,T.$ We assume $\deg\Delta=6.$ Let $\pi:X\to\mathbb{P}^2$ be a normal triple cover with branch divisor $\Delta,$ i.e. $\pi$ is ramified…

Algebraic Geometry · Mathematics 2012-11-13 Taketo Shirane

Let $E$ be a holomorphic vector bundle on a compact K\"ahler manifold $X$. If we fix a metric $h$ on $E$, we get a Laplace operator $\Delta$ acting upon smooth sections of $E$ over $X$. Using the zeta function of $\Delta$, one defines its…

dg-ga · Mathematics 2009-10-30 H. Gillet , C. Soulé

Given a smooth projective curve X, we give effective very ampleness bounds for generalized theta divisors on the moduli spaces $SU_X(r,d)$ and $U_X(r,d)$ of semistable vector bundles of rank r and degree d on X with fixed, respectively…

Algebraic Geometry · Mathematics 2007-05-23 Eduardo Esteves , Mihnea Popa

We discuss stability of square root domains for uniformly elliptic partial differential operators $L_{a,\Omega,\Gamma} = -\nabla\cdot a \nabla$ in $L^2(\Omega)$, with mixed boundary conditions on $\partial \Omega$, with respect to additive…

Analysis of PDEs · Mathematics 2014-11-19 Fritz Gesztesy , Steve Hofmann , Roger Nichols

Given a closed subscheme $Z$ of a polarized abelian variety $(A,\ell)$ we define its vanishing threshold with respect to $\ell$ and relate it to the Seshadri constant of the ideal defining $Z.$ As a particular case, we introduce the notion…

Algebraic Geometry · Mathematics 2025-05-12 Nelson Alvarado

We prove that projectivity is an open condition for deformations of algebraic spaces with rational singularities. V.2: references updated and corrected.

Algebraic Geometry · Mathematics 2021-05-25 János Kollár

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_g=C^{(2)}_g be the second symmetric product of a very general curve of genus g. We reduce the problem of describing the ample cone on X_g to a problem involving the Seshadri constant of a point on X_{g-1}. Using this we recover a…

Algebraic Geometry · Mathematics 2007-05-23 J. Ross

We prove that: I. For every regular Lindel\"of space $X$ if $|X|=\Delta(X)$ and $\mathrm{cf}|X|\ne\omega$, then $X$ is maximally resolvable; II. For every regular countably compact space $X$ if $|X|=\Delta(X)$ and $\mathrm{cf}|X|=\omega$,…

General Topology · Mathematics 2023-01-31 A. E. Lipin

To analyze the absolute condition number of multivariate polynomial interpolation on Lissajous-Chebyshev node points, we derive upper and lower bounds for the respective Lebesgue constant. The proof is based on a relation between the…

Numerical Analysis · Mathematics 2017-11-13 Peter Dencker , Wolfgang Erb , Yurii Kolomoitsev , Tetiana Lomako

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

We establish an improvement of Philippon's zero estimates primarily in the multiplicity setting. The improvement is made possible by a more geometric approach and in particular the use of Seshadri constants.

Number Theory · Mathematics 2007-10-15 Michael Nakamaye , Nicolas Ratazzi

The purpose of this note is to point out an elementary but somewhat surprising connection between the work of Buser and Sarnak on lengths of periods of abelian varieties and the Seshadri constants measuring the local positivity of theta…

alg-geom · Mathematics 2008-02-03 Robert Lazarsfeld

Let $X$ be a normal projective variety equipped with an action of a semisimple algebraic group $G$, and assume that $X$ contains a unique closed orbit. Let $B$ be a Borel subgroup of $G$ and let $E$ be a $B$-equivariant vector bundle on…

Algebraic Geometry · Mathematics 2025-11-12 Praveen Kumar Roy , Pinakinath Saha

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

We prove, assuming that the conjecture of Lang and Vojta holds true, that there is a uniform bound on the number of stably integral points in the complement of the theta divisor on a principally polarized abelian surface defined over a…

Algebraic Geometry · Mathematics 2007-05-23 Dan Abramovich , Kenji Matsuki