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We prove that, on a smooth threefold, pseudoeffective divisors with closed and one-dimensional diminished base locus have birationally a Fujita-Zariski decomposition.

Algebraic Geometry · Mathematics 2013-08-28 Enrica Floris

Using currents with minimal singularities, we construct pointwise minimal multiplicities for a real pseudo-effective $(1,1)$-class $\alpha$ on a compact complex $n$-fold $X$, which are the local obstructions to the numerical effectivity of…

Algebraic Geometry · Mathematics 2016-09-07 Sebastien Boucksom

We study divisors in the blow-up of $\mathbb{P}^n$ at points in general position that are non-special with respect to the notion of linear speciality introduced in [5]. We describe the cohomology groups of their strict transforms via the…

Algebraic Geometry · Mathematics 2017-02-14 Olivia Dumitrescu , Elisa Postinghel

We compute the facets of the effective and movable cones of divisors on the blow-up of $\mathbb{P}^n$ at $n+3$ points in general position. Given any linear system of hypersurfaces of $\mathbb{P}^n$ based at $n+3$ multiple points in general…

Algebraic Geometry · Mathematics 2015-10-01 Maria Chiara Brambilla , Olivia Dumitrescu , Elisa Postinghel

We study the cone of Moriwaki divisors on \bar{M}_g by means of augmented base loci. Using a result of Moriwaki, we prove that an R-divisor D satisfies the strict Moriwaki inequalities if and only if the augmented base locus of D is…

Algebraic Geometry · Mathematics 2016-09-07 Salvatore Cacciola , Angelo Felice Lopez , Filippo Viviani

Given a formal flat meromorphic connection over an excellent scheme over a field of characteristic zero, in a previous paper we established existence of good formal structures and a good Deligne-Malgrange lattice after suitably blowing up.…

Algebraic Geometry · Mathematics 2019-03-11 Kiran S. Kedlaya

This paper is an enhancement of the previous note "Explicit computations of Zariski decompositions on P_Z^1". In this paper, we observe several properties of a certain kind of an arithmetic divisor D on the n-dimensional projective space…

Algebraic Geometry · Mathematics 2015-01-14 Atsushi Moriwaki

We study graded rings associated to big divisors on LC pairs whose difference with the log-canonical divisor is nef. For divisors that are positive enough at the LC centers of the pair, we prove the finite generation of such rings if the…

Algebraic Geometry · Mathematics 2014-01-14 Salvatore Cacciola

We describe the normal stable surfaces with K^2=2p_g-3 and p_g>14 whose only non canonical singularity is a cyclic quotient singularity of type 1/4k(1,2k-1) and the corresponding locus D inside the KSBA moduli space of stable surfaces. More…

Algebraic Geometry · Mathematics 2025-02-25 Ciro Ciliberto , Rita Pardini

Given a projective hyper-K\"ahler manifold $X$, we study the asymptotic base loci of big divisors on $X$. We provide a numerical characterization of these loci and study how they vary while moving a big divisor class in the big cone, using…

Algebraic Geometry · Mathematics 2024-06-27 Francesco Antonio Denisi , Ángel David Ríos Ortiz

In this paper we study Zariski Decomposition with support in a negative definite cycle, a variation introduced by Y. Miyaoka. We provide two extensions of the original statement, which was originally meant for effective $\Q$-divisors: we…

Algebraic Geometry · Mathematics 2013-08-06 Roberto Laface

For a compact hyperk\"ahler manifold X, we show certain Zariski decomposition for every pseudo-effective R-divisor, and give a sufficient condition for X to be bimeromorphic to a (holomorphic) Lagrangian fibration. We also prove that any…

Algebraic Geometry · Mathematics 2014-04-30 Daisuke Matsushita , De-Qi Zhang

Let $(X,D)$ be an open log del Pezzo surface of rank one, that is, $X$ is a normal projective surface of Picard rank one, the boundary $D$ is a reduced nonzero divisor on $X$, and the anti-log canonical divisor $-(K_X+D)$ is ample. We show…

Algebraic Geometry · Mathematics 2025-08-20 Karol Palka , Tomasz Pełka

We show that any pseudo-effective divisor on a normal surface decomposes uniquely into its "integral positive" part and "integral negative" part, which is an integral analog of Zariski decompositions. By using this decomposition, we give…

Algebraic Geometry · Mathematics 2020-11-18 Makoto Enokizono

In this note we introduce a Waldschmidt decomposition of divisors which might be viewed as a generalization of Zariski decomposition based on the effectivity rather than the nefness of divisors. As an immediate application we prove a…

Algebraic Geometry · Mathematics 2018-02-27 Marcin Dumnicki , Tomasz Szemberg , Justyna Szpond

Zariski decomposition plays an important role in the theory of algebraic surfaces due to many applications. For irreducible symplectic manifolds Boucksom provided a characterization of his divisorial Zariski decomposition in terms of the…

Algebraic Geometry · Mathematics 2026-03-26 Michał Kapustka , Giovanni Mongardi , Gianluca Pacienza , Piotr Pokora

In this article, we consider the projective bundle $\mathbb{P}_X(E)$ over a smooth complex projective variety $X$, where $E$ is a semistable bundle on $X$ with $c_2(End(E)) =0$. We give a necessary and sufficient condition to get the…

Algebraic Geometry · Mathematics 2021-02-19 Snehajit Misra

We carry out a detailed intersection theoretic analysis of the Deligne-Mumford compactification of the divisor on M_{10} consisting of curves sitting on K3 surfaces. This divisor is not of classical Brill-Noether type, and is known to give…

Algebraic Geometry · Mathematics 2007-05-23 Gavril Farkas , Mihnea Popa

Let $X$ be the blowup of $\mathbb{P}^3$ at eight very general points. We give a complete description of its nef and effective cones. Moreover, we show that there exists a rational polyhedral fundamental domain for the action of a certain…

Algebraic Geometry · Mathematics 2023-05-18 Isabel Stenger , Zhixin Xie

We prove that the moduli space of Calabi-Yau 3-folds coming from eight planes of $P^3$ in general positions is not modular. In fact we show the stronger statement that the Zariski closure of the monodromy group is actually the whole…

Algebraic Geometry · Mathematics 2007-09-10 Ralf Gerkmann , Sheng Mao , Kang Zuo
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