English
Related papers

Related papers: Effective base point freeness on normal surfaces

200 papers

The article proves the Infinitesimal Torelli theorem for surfaces subject to the following conditions: 1) the canonical bundle of a surface is ample and generated by its global sections, 2)the geometric genus $p_g \geq 4$, 3) the…

Algebraic Geometry · Mathematics 2018-03-06 Igor Reider

We sharpen and generalize the dimension growth bounds for the number of points of bounded height lying on an irreducible algebraic variety of degree $d$, over any global field. In particular, we focus on the affine hypersurface situation by…

Number Theory · Mathematics 2025-12-05 Raf Cluckers , Pierre Dèbes , Yotam I. Hendel , Kien Huu Nguyen , Floris Vermeulen

In this paper, we show how to prove the basepoint-freeness for linear systems on irregular varieties inductively. For instance, we prove that Fujita's conjecture holds for irregular varieties of dimension $\mathnormal{n}$ with a nef…

Algebraic Geometry · Mathematics 2025-09-17 Houari Benammar Ammar

This paper proposes a Fujita-type freeness conjecture for semi-log canonical pairs. We prove it for curves and surfaces by using the theory of quasi-log schemes and give some effective very ampleness results for stable surfaces and semi-log…

Algebraic Geometry · Mathematics 2017-01-26 Osamu Fujino

In the present article we work out a relative setup of generic structures on surface singularities. We fix an analytic type on a subgraph of a rational homology sphere resolution graph $\mathcal{T}$ and we choose a relatively generic normal…

Algebraic Geometry · Mathematics 2021-12-30 János Nagy

We obtain an effective version of Matsusaka's theorem for arbitrary smooth algebraic surfaces in positive characteristic, which provides an effective bound on the multiple which makes an ample line bundle D very ample. The proof for…

Algebraic Geometry · Mathematics 2016-01-20 Gabriele Di Cerbo , Andrea Fanelli

We obtain a complete description of the effective cone of $C_{g-2}$ when $C$ is a general curve of genus $g \geq 6,$ as well as a new bound in the case where $C$ is a smooth plane quintic. In addition, we obtain a new virtual bound for the…

Algebraic Geometry · Mathematics 2010-05-24 Yusuf Mustopa

In this paper, we revisit the problem of classifying real algebraic and semialgebraic sets by their topological types, focusing on establishing the effectiveness of bounds rather than deriving new quantitative estimates. Building on Hardt's…

Algebraic Geometry · Mathematics 2024-12-24 Kartoue Mady Demdah , Ibrahim Nonkane

We present a new class of examples of base points for the generalized theta divisor on the moduli space of semistable vector bundles of trivial determinant on a compact Riemann surface and we prove that for sufficiently large rank the base…

Algebraic Geometry · Mathematics 2009-10-31 Mihnea Popa

We define a categorical birational invariant for minimal geometrically rational surfaces with a conic bundle structure over a perfect field via components of a natural semiorthogonal decomposition. Together with the similar known result on…

Algebraic Geometry · Mathematics 2019-09-30 Marcello Bernardara , Sara Durighetto

We give a new criterion for when a resolution of a surface of general type with canonical singularities has big cotangent bundle and a new lower bound for the values of $d$ for which there is a surface with big cotangent bundle that is…

Algebraic Geometry · Mathematics 2019-12-23 Bruno De Oliveira , Michael L Weiss

We show that the anti-canonical bundle of any $\mathbb Q$-factorial surface is numerically effective if and only if it is pseudo-effective. To prove this, we establish a numerical non-vanishing theorem for surfaces polarized with…

Algebraic Geometry · Mathematics 2024-10-22 Jihao Liu , Lingyao Xie

We prove a surface embedding theorem for 4-manifolds with good fundamental group in the presence of dual spheres, with no restriction on the normal bundles. The new obstruction is a Kervaire-Milnor invariant for surfaces and we give a…

Geometric Topology · Mathematics 2024-09-04 Daniel Kasprowski , Mark Powell , Arunima Ray , Peter Teichner

We give the classification of globally generated vector bundles of rank $2$ on a smooth quadric surface with $c_1\le (2,2)$ in terms of the indices of the bundles, and extend the result to arbitrary higher rank case. We also investigate…

Algebraic Geometry · Mathematics 2014-06-16 Edoardo Ballico , Sukmoon Huh , Francesco Malaspina

We prove a global uniform Artin-Rees lemma type theorem for sections of ample line bundles over smooth projective varieties. This result is used to prove an Artin-Rees lemma for the polynomial ring with uniform degree bounds. The proof is…

Complex Variables · Mathematics 2013-06-26 Johannes Lundqvist

Recent literature on Weil-Petersson random hyperbolic surfaces has met a consistent obstacle: the necessity to condition the model, prohibiting certain rare geometric patterns (which we call tangles), such as short closed geodesics or…

Geometric Topology · Mathematics 2025-10-15 Nalini Anantharaman , Laura Monk

The paper contains theorems on extending sections of line bundles from divisors to the ambient space, inspired by various results of Siu, Kawamata, and especially Hacon-McKernan and Takayama. Applications are given to basepoint-freeness, to…

Algebraic Geometry · Mathematics 2009-12-20 Lawrence Ein , Mihnea Popa

This paper explores the cohomological consequences of the existence of moduli spaces for flat bundles with bounded rank and irregularity at infinity and gives unconditional proofs. Namely, we prove the existence of a universal bound for the…

Algebraic Geometry · Mathematics 2025-02-26 Haoyu Hu , Jean-Baptiste Teyssier

We formulate and establish a generalization of Koll\'ar's injectivity theorem for adjoint bundles twisted by suitable multiplier ideal sheaves. As applications, we generalize Koll\'ar's torsion-freeness, Koll\'ar's vanishing theorem, and a…

Complex Variables · Mathematics 2022-05-24 Osamu Fujino , Shin-ichi Matsumura

Using Langer's construction of Bridgeland stability conditions on normal surfaces, we prove Reider-type theorems generalizing the work done by Arcara-Bertram in the smooth case. Our results still hold in positive characteristic or when…

Algebraic Geometry · Mathematics 2024-11-15 Anne Larsen , Anda Tenie