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We derive a general upper bound for the number of incidences with $k$-dimensional varieties in ${\mathbb R}^d$. The leading term of this new bound generalizes previous bounds for the special cases of $k=1, k=d-1,$ and $k= d/2$, to every…

Combinatorics · Mathematics 2018-09-13 Thao Do , Adam Sheffer

Let $f: S\longrightarrow B$ be a non-trivial fibration from a complex projective smooth surface $S$ to a smooth curve $B$ of genus $b$. Let $c_f$ the Clifford index of the generic fibre $F$ of $f$. In [arXiv:1401.7502v4] it is proved that…

Algebraic Geometry · Mathematics 2017-10-03 Filippo Francesco Favale , Juan Carlos Naranjo , Gian Pietro Pirola

A well known upper bound for the spectral radius of a graph, due to Hong, is that $\mu_1^2 \le 2m - n + 1$. It is conjectured that for connected graphs $n - 1 \le s^+ \le 2m - n + 1$, where $s^+$ denotes the sum of the squares of the…

Combinatorics · Mathematics 2015-09-21 Clive Elphick , Felix Goldberg , Miriam Farber , Pawel Wocjan

Given a triple covering $X$ of genus $g$ of a general (in the sense of Brill-Noether) curve $C$ of genus $h$, we show the existence of base-point-free pencils of degree $d$ which are not composed with the triple covering for any $d\ge…

alg-geom · Mathematics 2008-02-03 Takao Kato , Changho Keem , Akira Ohbuchi

We give a combinatorial upper bound for the gonality of a curve that is defined by a bivariate Laurent polynomial with given Newton polygon. We conjecture that this bound is generically attained, and provide proofs in a considerable number…

Algebraic Geometry · Mathematics 2012-01-17 Wouter Castryck , Filip Cools

We prove that on a closed surface of genus $g$, the cardinality of a set of simple closed curves in which any two are non-homotopic and intersect at most once is $\lesssim g^2 \log(g)$. This bound matches the largest known constructions to…

Geometric Topology · Mathematics 2018-07-17 Joshua Evan Greene

Let g be an integer greater than 1. A uniform version of the Parshin-Arakelov theorem on the finiteness of the set of non-isotrivial curves of genus g over a function field, with fixed degeneracy locus, is proved. This is applied to obtain…

Algebraic Geometry · Mathematics 2007-05-23 Lucia Caporaso

Bounds are proved for the connective constant \mu\ of an infinite, connected, \Delta-regular graph G. The main result is that \mu\ \ge \sqrt{\Delta-1} if G is vertex-transitive and simple. This inequality is proved subject to weaker…

Combinatorics · Mathematics 2013-05-02 Geoffrey R. Grimmett , Zhongyang Li

The Grassmann convexity conjecture gives a conjectural formula for the maximal total number of real zeros of the consecutive Wronskians of an arbitrary fundamental solution to a disconjugate linear ordinary differential equation with real…

Classical Analysis and ODEs · Mathematics 2021-10-15 Nicolau C. Saldanha , Boris Shapiro , Michael Shapiro

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

Let $G$ be a graph with chromatic number $\chi$, maximum degree $\Delta$ and clique number $\omega$. Reed's conjecture states that $\chi \leq \lceil (1-\varepsilon)(\Delta + 1) + \varepsilon\omega \rceil$ for all $\varepsilon \leq 1/2$. It…

Combinatorics · Mathematics 2018-10-17 Marthe Bonamy , Thomas Perrett , Luke Postle

We investigate combinatorial bounds for the total Tjurina numbers of plane curve arrangements. Focusing on arrangements of lines and conics in $\mathbb{P}^2$ that admit only ordinary quasi-homogeneous singularities, we derive new structural…

Algebraic Geometry · Mathematics 2026-02-27 Piotr Pokora

Consider a Riemannian manifold with bounded Ricci curvature $|\Ric|\leq n-1$ and the noncollapsing lower volume bound $\Vol(B_1(p))>\rv>0$. The first main result of this paper is to prove that we have the $L^2$ curvature bound…

Differential Geometry · Mathematics 2020-10-29 Wenshuai Jiang , Aaron Naber

Simple boundary expressions for the k-th power of the cotangent line class on the moduli space of stable 1-pointed genus g curves are found for k >= 2g. The method is by virtual localization on the moduli space of maps to the projective…

Algebraic Geometry · Mathematics 2010-04-23 Xiaobo Liu , Rahul Pandharipande

The problem of constructing curves with many points over finite fields has received considerable attention in the recent years. Using the class field theory approach, we construct new examples of curves ameliorating some of the known…

Number Theory · Mathematics 2016-11-16 Pavel Solomatin

We prove the generalised Tate conjecture for H^3 of products of elliptic curves over finite fields, by slightly modifying an argument of M. Spiess concerning the Tate conjecture. We prove it fully if the elliptic curves run among at most 3…

Algebraic Geometry · Mathematics 2011-01-11 Bruno Kahn

We study genus 2 covers of relative elliptic curves over an arbitrary base in which 2 is invertible. Particular emphasis lies on the case that the covering degree is 2. We show that the data in the "basic construction" of genus 2 covers of…

Algebraic Geometry · Mathematics 2007-05-23 Claus Diem

This is an addendum to the paper of Braun and Fl{\o}ystad ([BF]) on the bound for the degree of a smooth surface in $\pfour$ not of general type. Using their construction and the regularity of curves in $\pthree$, one may lower the bound a…

alg-geom · Mathematics 2015-06-30 Michele Cook

We report a universal improvement to the standard Robertson--Schr\"odinger uncertainty relation. Our result shows that the Robertson--Schr\"odinger lower bound can be supplemented by a new noncommutativity-induced term. This term represents…

Quantum Physics · Physics 2026-05-19 Gen Kimura , Aina Mayumi , Hiromichi Ohno , Jaeha Lee , Dariusz Chruściński

Consider a closed curve of length $2\pi$ with curvature $\kappa(s)$ and the Schr\"odinger operator $H$ with $\kappa^2$ as the potential term. Let $\lambda_\Gamma$ be the lowest eigenvalue of $H$. The Ovals Conjecture proposed by Benguria…

Mathematical Physics · Physics 2025-05-27 Helmut Linde