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Related papers: On submaximal curves in fake projective planes

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We find explicit equations of a new pair of fake projective planes, labeled by $(C18,p=3,\{2I\})$ in the Cartwright-Steger classification. Our method involves starting with known equations of a commensurable fake projective plane…

Algebraic Geometry · Mathematics 2025-12-04 Lev Borisov , Bojue Wang

We generalize results by Wakabayashi and Orevkov about rational cuspidal curves on the projective plane to that on $\mathbb{Q}$-homology projective planes. It turns out that the result is exactly the same as the projective plane case under…

Algebraic Geometry · Mathematics 2017-05-26 R. V. Gurjar , DongSeon Hwang , Sagar Kolte

It is known for a long time that a nonsingular real algebraic curve of degree 2k in the projective plane cannot have more than 7/2*k^2-9/4*k+3/2$ even ovals. We show here that this upper bound is asymptotically sharp, that is to say we…

Algebraic Geometry · Mathematics 2007-05-23 Erwan brugalle

Our concern is a nonsingular plane curve defined over a finite field of q elements which includes all the rational points of the projective plane over the field. The possible degree of such a curve is at least q+2. We prove that nonsingular…

Algebraic Geometry · Mathematics 2009-09-11 Masaaki Homma , Seon Jeong Kim

We examine how the Seshadri constant of an ample line bundle at a very general point of an algebraic surface can carry important global geometric information about the surface. In particular, we obtain a numerical criterion for when a…

Algebraic Geometry · Mathematics 2007-05-23 Michael Nakamaye

We determine non-Hopf hypersurfaces with constant mean curvature in the complex projective plane which attain equality in a basic inequality between the maximum Ricci curvature and the squared mean curvature.

Differential Geometry · Mathematics 2017-02-09 Toru Sasahara

We characterise, in terms of Dixmier-Ohno invariants, the types of singularities that a plane quartic curve can have. We then use these results to obtain new criteria for determining the stable reduction types of non-hyperelliptic curves of…

Number Theory · Mathematics 2024-08-30 Raymond van Bommel , Jordan Docking , Reynald Lercier , Elisa Lorenzo García

We establish an avoidance criterion for families of holomorphic curves from the unit disk in complex plane to the complex projective space that omit sufficiently many moving hypersurfaces in pointwise general position. Furthermore, we study…

Complex Variables · Mathematics 2026-05-11 Gopal Datt , Rahul Gogoi , Kushal Lalwan

We prove discrete Helly-type theorems for pseudohalfplanes, which extend recent results of Jensen, Joshi and Ray about halfplanes. Among others we show that given a family of pseudohalfplanes $\cal H$ and a set of points $P$, if every…

Combinatorics · Mathematics 2021-10-05 Balázs Keszegh

In the present note we prove a conjecture of Demailly for finite sets of sufficiently many very general points in projective spaces. This gives a lower bound on Waldschmidt constants of such sets. Waldschmidt constants are asymptotic…

Algebraic Geometry · Mathematics 2017-01-19 Grzegorz Malara , Tomasz Szemberg , Justyna Szpond

We give the first examples of nef line bundles on smooth projective varieties over finite fields which are not semi-ample. More concretely, we find smooth curves on smooth projective surfaces over finite fields such that the normal bundle…

Algebraic Geometry · Mathematics 2007-12-14 Burt Totaro

In Dubouloz and Mangolte (Fake real planes: exotic affine algebraic models of $\mathbb{R}^{2}$, arXiv:1507.01574, 2015) we define and partially classify fake real planes, that is, minimal complex surfaces with conjugation whose real locus…

Algebraic Geometry · Mathematics 2022-06-22 Adrien Dubouloz , Frédéric Mangolte

Following Kraitchik and Lehmer, we say that a positive integer $n\equiv1\pmod 8$ is an $x$-pseudosquare if it is a quadratic residue for each odd prime $p\le x$, yet is not a square. We extend this defintion to algebraic curves and say that…

Number Theory · Mathematics 2010-10-22 Reza R. Farashahi , Igor E. Shparlinski

We define and study a version of Seshadri constant for ample line bundles in positive characteristic. We prove that lower bounds for this constant imply the global generation or very ampleness of the corresponding adjoint line bundle. As a…

Algebraic Geometry · Mathematics 2014-05-06 Mircea Mustata , Karl Schwede

This paper investigates the Castelnuovo-Mumford regularity of the generic hyperplane section of projective curves in positive characteristic case, and yields an application to a sharp bound on the regularity for nondegenerate projective…

Algebraic Geometry · Mathematics 2007-05-23 Edoardo Ballico , Chikashi Miyazaki

Pseudospectral approximation provides a means to approximate the dynamics of delay differential equations (DDE) by ordinary differential equations (ODE). This article develops a computer-aided algorithm to determine the distance between the…

Dynamical Systems · Mathematics 2024-05-14 Shane Kepley , Babette A. J. de Wolff

In this work we study the \emph{Saito number} of a plane curve and we present a method to determine the minimal Saito number for plane curves in a given equisingularity class, that gives rise to an actual algorithm. In particular…

Algebraic Geometry · Mathematics 2024-06-21 Yohann Genzmer , Marcelo E. Hernandes

We study holomorphic curves $f:\C\longrightarrow \C^3$ avoiding four complex hyperplanes and a real subspace of real dimension four or five in $\C^3$. We show that the projection of $f$ into the complex projective space $\C P^2$ is not…

Complex Variables · Mathematics 2019-02-04 Fathi Haggui , Abdessami Jalled

Let $P$ be a set of $n$ points in the real plane contained in an algebraic curve $C$ of degree $d$. We prove that the number of distinct distances determined by $P$ is at least $c_d n^{4/3}$, unless $C$ contains a line or a circle. We also…

Metric Geometry · Mathematics 2016-07-20 János Pach , Frank de Zeeuw

In this article, we study isomorphisms between complements of irreducible curves in the projective plane $\mathbb{P}^2$, over an arbitrary algebraically closed field. Of particular interest are rational unicuspidal curves. We prove that if…

Algebraic Geometry · Mathematics 2023-06-22 Mattias Hemmig