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Toric log del Pezzo surfaces correspond to convex lattice polygons containing the origin in their interior and having only primitive vertices. An upper bound on the volume and on the number of boundary lattice points of these polygons is…

Algebraic Geometry · Mathematics 2010-05-02 Alexander M. Kasprzyk , Maximilian Kreuzer , Benjamin Nill

We prove effective versions of algebraic and analytic Lang's conjectures for product-quotient surfaces of general type with $P_g=0$ and $c_1^2=c_2$.

Algebraic Geometry · Mathematics 2019-06-06 Julien Grivaux , Juliana Restrepo Velasquez , Erwan Rousseau

Stable surfaces and their log analogues are the type of varieties naturally occuring as boundary points in moduli spaces. We extend classical results of Kodaira and Bombieri to this more general setting: if $(X,\Delta)$ is a stable log…

Algebraic Geometry · Mathematics 2014-04-15 Wenfei Liu , Sönke Rollenske

We give a notion of ordinary Enriques surfaces and their canonical lifts in any positive characteristic, and we prove Torelli-type results for this class of Enriques surfaces.

Algebraic Geometry · Mathematics 2021-01-15 Roberto Laface , Sofia Tirabassi

We study minimal surfaces X of general type with $K^2_X=6p_g-14$ and $q(X)>0$ such that $K_X$ is ample, the image of the canonical map is a canonically embedded surface of general type and the canonical map is not birational. The main…

alg-geom · Mathematics 2016-08-30 Margarida Mendes Lopes , Rita Pardini

We classify normal stable surfaces with $K_X^2 = 1$, $p_g = 2$ and $q=0$ with a unique singular point which is a non-canonical T-singularity, thus exhibiting two divisors in the main component and a new irreducible component of the moduli…

Algebraic Geometry · Mathematics 2020-12-11 Marco Franciosi , Rita Pardini , Julie Rana , Sönke Rollenske

Recently a simple proof of the generalizations of Hawking's black hole topology theorem and its application to topological black holes for higher dimensional ($n\geq 4$) spacetimes was given \cite{rnew}. By applying the associated new line…

General Relativity and Quantum Cosmology · Physics 2010-06-29 István Rácz

We extend fundamental inequalities related to the canonical map of surfaces of general type to positive characteristic. Next, we classify surfaces on the Noether lines, i.e., even and odd Horikawa surfaces, in positive characteristic. We…

Algebraic Geometry · Mathematics 2013-01-11 Christian Liedtke

We construct a surface with irregularity $q=2,$ geometric genus $p_g=3,$ self-intersection of the canonical divisor $K^2=16$ and canonical map of degree $16.$

Algebraic Geometry · Mathematics 2015-06-22 Carlos Rito

Let $S$ be a smooth complex minimal surface of general type with $p_g:=h^0(K_S)\ge 4$ whose canonical map is generically finite of odd degree $d>1$ onto a surface $\Sigma$. We assume that the general canonical curve of $S$ is smooth and…

Algebraic Geometry · Mathematics 2026-04-13 Margarida Mendes Lopes , Rita Pardini , Roberto Pignatelli

We give an algorithm that, for a given value of the geometric genus $p_g,$ computes all regular product-quotient surfaces with abelian group that have at most canonical singularities and have canonical system with at most isolated base…

Algebraic Geometry · Mathematics 2020-03-26 Christian Gleissner , Roberto Pignatelli , Carlos Rito

We introduce the notion of generalized MR log canonical surfaces and establish the minimal model theory for generalized MR log canonical surfaces in full generality.

Algebraic Geometry · Mathematics 2020-12-03 Osamu Fujino

We discuss the relative log minimal model theory for log surfaces in the analytic setting. More precisely, we show that the minimal model program, the abundance theorem, and the finite generation of log canonical rings hold for log pairs of…

Algebraic Geometry · Mathematics 2026-04-15 Nao Moriyama

In this paper, we prove a Morse index theorem for the index form of regular Lagrangian system with selfadjoint boundary condition.

Differential Geometry · Mathematics 2007-05-23 Chaofeng Zhu

In this paper we propose an approach to investigate the canonical rings of surfaces of general type whose canonical system has isolated base points and yields a birational map onto its image. We apply then the method in the concrete case of…

Algebraic Geometry · Mathematics 2007-05-23 I. C. Bauer , F. Catanese , R. Pignatelli

In this paper, we study the geometry of surfaces with the generalised simple lift property. This work generalises previous results by Bernstein and Tinaglia, and it is motivated by the fact that leaves of a minimal lamination obtained as a…

Geometric Topology · Mathematics 2019-10-09 Francesca Tripaldi

We prove that any compact surface with constant positive curvature and conical singularities can be decomposed into irreducible components of standard shape, glued along geodesic arcs connecting conical singularities. This is a spherical…

Geometric Topology · Mathematics 2022-01-05 Guillaume Tahar

The homogeneous minimal hypersurfaces in $S^n$ have $g = 1,2,3,4$, or $6$ distinct (constant) principal curvatures. While the Morse index and nullity have been calculated for all such hypersurfaces having $g = 1,2,3$, it has remained an…

Differential Geometry · Mathematics 2023-12-18 Gavin Ball , Jesse Madnick , Uwe Semmelmann

We define topological invariants of regular Lagrangian fibrations using the integral affine structure on the base space and we show that these coincide with the classes known in the literature. We also classify all symplectic types of…

Symplectic Geometry · Mathematics 2015-05-14 D. Sepe

We survey some results on real rational surfaces focused on their topology and their birational geometry.

Algebraic Geometry · Mathematics 2025-05-26 Frederic Mangolte