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We introduce and begin the topological study of real rational plane curves, all of whose inflection points are real. The existence of such curves is a corollary of results in the real Schubert calculus, and their study has consequences for…

Algebraic Geometry · Mathematics 2010-03-29 Viatcheslav Kharlamov , Frank Sottile

For orbifolds admitting a crepant resolution and satisfying a hard Lefschetz condition, we formulate a conjectural equivalence between the Gromov-Witten theories of the orbifold and the resolution. We prove the conjecture for the…

Algebraic Geometry · Mathematics 2007-05-23 Jim Bryan , Tom Graber

We derive a family of $L^p$ estimates of the X-Ray transform of positive measures in $\mathbb R^d$, which we use to construct a $\log R$-loss counterexample to the Mizohata-Takeuchi conjecture for every $C^2$ hypersurface in $\mathbb R^d$…

Classical Analysis and ODEs · Mathematics 2025-03-13 Hannah Cairo

We consider some variations on the classical method of Runge for effectively determining integral points on certain curves. We first prove a version of Runge's theorem valid for higher-dimensional varieties, generalizing a uniform version…

Number Theory · Mathematics 2008-05-12 Aaron Levin

We propose a linear version of the weighted bounded negativity conjecture. It considers a smooth projective surface $X$ over an algebraically closed field of characteristic zero and predicts the existence of a common lower bound on…

Algebraic Geometry · Mathematics 2025-01-27 Carlos Galindo , Francisco Monserrat , Elvira Pérez-Callejo

We study negative curves on surfaces obtained by blowing up special configurations of points in the complex projective palne. Our main results concern the following configurations: very general points on a cubic, 3-torsion points on an…

In this paper, we study the cones of higher codimension (pseudo)effective cycles on point blow-ups of projective space. We determine bounds on the number of points for which these cones are generated by the classes of linear cycles, and for…

Algebraic Geometry · Mathematics 2016-11-30 Izzet Coskun , John Lesieutre , John Christian Ottem

The study of entire holomorphic curves contained in projective algebraic varieties is intimately related to fascinating questions of geometry and number theory -- especially through the concepts of curvature and positivity which are central…

Algebraic Geometry · Mathematics 2020-02-14 Jean-Pierre Demailly

We show that any random vector uniformly distributed on any hyperplane projection of $B_1^n$ or $B_\infty^n$ verifies the variance conjecture $$\text{Var}|X|^2\leq C\sup_{\xi\in S^{n-1}}\E<X,\xi>^2\E|X|^2.$$ Furthermore, a random vector…

Functional Analysis · Mathematics 2012-09-20 David Alonso-Gutiérrez , Jesús Bastero

The Green-Griffiths-Lang conjecture stipulates that for every projective variety $X$ of general type over ${\mathbb C}$, there exists a proper algebraic subvariety of $X$ containing all non constant entire curves $f:{\mathbb C}\to X$. Using…

Algebraic Geometry · Mathematics 2015-03-13 Jean-Pierre Demailly

We consider blowups at a general point of weighted projective planes and, more generally, of toric surfaces with Picard number one. We give a unifying construction of negative curves on these blowups such that all previously known families…

Algebraic Geometry · Mathematics 2021-09-17 Javier González-Anaya , José Luis González , Kalle Karu

We present counterexamples to Fujita's conjecture in positive characteristics. Precisely, we show that over any algebraically closed field $k$ of characteristic $p>0$ and for any positive integer $m$, there exists a smooth projective…

Algebraic Geometry · Mathematics 2022-01-06 Yi Gu , Lei Zhang , Yongming Zhang

We formulate an Iwasawa main conjecture for a higher rank Euler system for a general motive. We prove "one half" of the main conjecture under mild hypotheses. We also formulate a conjecture on "Darmon-type derivatives" of Euler systems and…

Number Theory · Mathematics 2022-03-17 Takenori Kataoka , Takamichi Sano

We give a reduction of the irregular case for the effective non-vanishing conjecture by virtue of the Fourier-Mukai transform. As a consequence, we reprove that the effective non-vanishing conjecture holds on algebraic surfaces.

Algebraic Geometry · Mathematics 2008-02-27 Qihong Xie

Let $\Gamma$ be a finite set, and $X\ni x$ a fixed klt germ. For any lc germ $(X\ni x,B:=\sum_{i} b_iB_i)$ such that $b_i\in \Gamma$, Nakamura's conjecture, which is equivalent to the ACC conjecture for minimal log discrepancies for fixed…

Algebraic Geometry · Mathematics 2022-04-15 Jingjun Han , Yujie Luo

We formulate the Secant Conjecture, which is a generalization of the Shapiro Conjecture for Grassmannians. It asserts that an intersection of Schubert varieties in a Grassmannian is transverse with all points real, if the flags defining the…

In the paper we develop a new method of proving non-speciality of a linear system with base fat points in general position. Using this method we show that the Hirschowitz-Harbourne Conjecture holds for systems with base points of equal…

Algebraic Geometry · Mathematics 2007-05-23 Marcin Dumnicki

We study the relationship between Iitaka fibrations and the conjecture on the existence of complements, assuming the good minimal model conjecture. In one direction, we show that the conjecture on the existence of complements implies the…

Algebraic Geometry · Mathematics 2023-01-13 Guodu Chen , Jingjun Han , Jihao Liu

We settle the conjecture posed by Sziklai on the number of points of a plane curve over a finite field under the assumption that the curve is nonsingular.

Algebraic Geometry · Mathematics 2014-01-21 Masaaki Homma , Seon Jeong Kim

Ioka and Nakamura (2001) proposed a simple jet model that is compatible with the peak luminosity-spectral lag relation, the peak luminosity-variability relation and various other relations in the Gamma-Ray Bursts. If the viewing angle is…

Astrophysics · Physics 2009-11-07 Ryo Yamazaki , Kunihito Ioka , Takashi Nakamura