Effective Boundedness Results in Algebraic Geometry

这个项目的目的是研究几何的不同方面之间的联系：二次几何和微分几何。具体地说，它讨论了在代数几何和微分几何中确实存在多少具有给定性质的几何对象的自然问题。这样的问题被称为“代数簇类的有界性”。该项目分为两个部分，其中PI将特别旨在了解与某些种类的变种(定义为多项式方程的零轨迹的几何对象)的有界性相关的不同几何方面以及这些结果的应用。其主要目的是开发可用于将低维几何中的经典结果扩展到更高维的方法，使用的技术源于过去20年发展起来的被称为“最小模型程序”的理论。其中一些结果将应用于数学物理中的弦理论。该项目的第一部分集中在Calabi-Yau簇的有界性上。尽管从许多角度来看，Calabi-Yau流形都是非常简单的代数变体，但对它们的有界性仍然知之甚少。该项目这一部分的主要目标是研究椭圆形纤维Calabi-Yau品种。众所周知，在低维上，它们满足有趣的有界性，PI打算将这些结果推广到任意维上。这些结果在极小模型程序、代数簇的分类和F-理论中都有应用。本项目的最后部分旨在探索类似于具有锥边奇点的卡勒-爱因斯坦度规理论的技术的含义。这个项目的主要动机是研究球商和更一般的高阶局部对称簇的环形紧化的比分几何。作为该项目的一部分，PI打算开发最终将适用于具有收缩负截面曲率的有限体积Kahler流形的紧致的技术。

The purpose of this project is to study connections between different aspects of geometry: birational geometry and differential geometry. Specifically, it deals with natural questions on how many geometric objects possessing given properties arising both in algebraic geometry and differential geometry do exist. Such questions are known as "boundedness of classes of algebraic varieties." The project is divided in two parts in which the PI will especially aim to understand different geometrical aspects related to the boundedness of certain classes of varieties (geometric objects defined as zero loci of polynomial equations) and applications of such results. The main aim is to develop methods that can be used to extend classical results in low-dimensional geometry to higher dimensions using techniques arising from the developed in the last 20 years theory known as the "minimal model program." Some of these results will have application to string theory in mathematical physics.The first part of the project focuses on boundedness of Calabi-Yau varieties. Even though Calabi-Yau manifolds are very simple algebraic varieties from many points of view, their boundedness properties are still poorly understood. The main goal of this part of the project is to study elliptic fibered Calabi-Yau varieties. It is known that in low dimensions they satisfy interesting boundedness properties and the PI intends to extend such results in arbitrary dimension. These results have applications to the minimal model program, the classification of algebraic varieties and F-theory. The last part of this project aims to explore the implications of similar techniques to the theory of Kahler-Einstein metric with cone-edge singularities. The main motivation for this project is the study of the birational geometry of toroidal compactifications of ball quotients and more generally of higher ranks locally symmetric varieties. As part of this project, the PI intends to develop techniques that eventually will work even with compactifications of finite volume Kahler manifolds with pinched negative sectional curvature.