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In this note, we construct a minimal surface of general type with geometric genus p g = 4, self-intersection of the canonical divisor K^2 = 32 and irregularity q = 1 such that its canonical map is an abelian cover of degree 16 of P^1 x P^1.

Algebraic Geometry · Mathematics 2019-07-31 Nguyen Bin

Let $A$ be a non-isotrivial almost ordinary abelian surface with possibly bad reductions over a global function field of odd characteristic $p$. Suppose $\Delta$ is an infinite set of positive integers, such that…

Number Theory · Mathematics 2025-04-10 Ruofan Jiang

We show that polarisations of type (1,...,1,2g+2) on g-dimensional abelian varieties are $\it{never}$ very ample, if $g\geq 3$. This disproves a conjecture of Debarre, Hulek and Spandaw. We also give a criterion for non-embeddings of…

Algebraic Geometry · Mathematics 2007-05-23 Jaya N. Iyer

An abelian cover is a finite morphism $X\to Y$ of varieties which is the quotient map for a generically faithful action of a finite abelian group $G$. Abelian covers with $Y$ smooth and $X$ normal were studied in…

Algebraic Geometry · Mathematics 2019-02-20 Valery Alexeev , Rita Pardini

In this paper we shall generalize the chamber structure of polarizations defined by Qin, and as an application we shall compute the Picard groups of moduli spaces of stable sheaves on a non-rational ruled surface.

alg-geom · Mathematics 2016-08-14 Kōta Yoshioka

The authors define an "anti-holomorphic" involution (or "real structure") on an ordinary Abelian variety (defined over a finite field k) to be an involution of the associated Deligne module (T,F,V) that exchanges F (the Frobenius) with V…

Number Theory · Mathematics 2017-03-22 Mark Goresky , Yung-sheng Tai

We give a bound on the number of points of order two on the theta divisor of a principally polarized abelian variety A. When A is the Jacobian of a curve C the result can be applied in estimating the number of effective square roots of a…

Algebraic Geometry · Mathematics 2012-02-08 Valeria Ornella Marcucci , Gian Pietro Pirola

Let $A$ be a non-isotrivial ordinary abelian surface over a global function field with good reduction everywhere. Suppose that $A$ does not have real multiplication by any real quadratic field with discriminant a multiple of $p$. We prove…

Number Theory · Mathematics 2020-08-11 Davesh Maulik , Ananth N. Shankar , Yunqing Tang

The Satake compactification of the moduli space of principally polarized abelian surfaces with a level two structure has a degree 8 endomorphism. The aim of this paper is to show that this result can be extended to other modular threefolds.…

Algebraic Geometry · Mathematics 2015-12-11 Sara Perna

Let V be a smooth quasi-projective complex surface such that the three first logarithmic plurigenera are equal to 1 and the logarithmic irregularity is equal to 2. We prove that the quasi-Albanese morphism of V is birational and there…

Algebraic Geometry · Mathematics 2023-02-03 Margarida Mendes Lopes , Rita Pardini , Sofia Tirabassi

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

We show that there exist flat surface bundles with closed leaves having non-trivial normal bundles. This leads us to compute the Abelianisation of surface diffeomorphism groups with marked points. We also extend a formula of Tsuboi that…

Geometric Topology · Mathematics 2014-10-01 Jonathan Bowden

Using a description of the cohomology of local systems on the moduli space of abelian surfaces with a full level two structure, together with a computation of Euler characteristics we find the isotypical decomposition, under the symmetric…

Number Theory · Mathematics 2025-03-05 Jonas Bergström , Fabien Cléry

In this paper we complete the determination of the index of factoriality of moduli spaces of semistable sheaves on an abelian or projective K3 surface $S$. If $v=2w$ is a Mukai vector, $w$ is primitive, $w^{2}=2$ and $H$ is a generic…

Algebraic Geometry · Mathematics 2015-03-19 Arvid Perego , Antonio Rapagnetta

Inspired by the Dolgachev-Nikulin-Pinkham mirror symmetry for lattice-polarized K3 surfaces, we study its analogue for abelian surfaces. In this paper, we introduce lattice-polarized abelian surfaces and construct their coarse moduli…

Algebraic Geometry · Mathematics 2026-02-10 Yu-Wei Fan , Kuan-Wen Lai

Let S be a smooth minimal complex projective surface of maximal Albanese dimension. Under the assumption that the canonical class of S is ample and the irregularity of S, q(S), is greater or equal to 5 we show that K^2>=…

Algebraic Geometry · Mathematics 2009-04-08 Margarida Mendes Lopes , Rita Pardini

We give a bound on which singularities may appear on Koll\'ar--Shepherd-Barron--Alexeev stable surfaces for a wide range of topological invariants and use this result to describe all stable numerical quintic surfaces (KSBA-stable surfaces…

Algebraic Geometry · Mathematics 2014-07-29 Julie Rana

We study moduli spaces of abelian varieties in positive characteristic, more specifically the moduli space of principally polarized abelian varieties on the one hand, and the analogous space with Iwahori type level structure, on the other…

Algebraic Geometry · Mathematics 2009-11-23 Ulrich Goertz , Chia-Fu Yu

This is a brief account of my results with George Boxer, Frank Calegari and Vincent Pilloni on the (potential) modularity of abelian surfaces.

Number Theory · Mathematics 2025-10-06 Toby Gee

To every abelian subvariety of a principally polarized abelian variety $(A, \mathcal{L})$ we canonically associate a numerical class in the N\'eron-Severi group of $A$. We prove that these classes are characterized by their intersection…

Algebraic Geometry · Mathematics 2015-10-06 Robert Auffarth
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