内容简介
Complex geometry is a highly attractive branch of modern mathematics that has witnessed many years of active and successful research and that has re- cently obtained new impetus from physicists interest in questions related to mirror symmetry. Due to its interactions with various other fields (differential, algebraic, and arithmetic geometry, but also string theory and conformal field theory), it has become an area with many facets. Also, there are a number of challenging open problems which contribute to the subjects attraction. The most famous among them is the Hodge conjecture, one of the seven one-million dollar millennium problems of the Clay Mathematics Institute. So, it seems likely t at this area will fascinate new generations for many years to come.
内页插图
目录
1 Local Theory
1.1 Holomorphic Functions of Several Variables
1.2 Complex and Hermitian Structures
1.3 Differential Forms
2 Complex Manifolds
2.1 Complex Manifolds: Definition and Examples
2.2 Holomorphic Vector Bundles
2.3 Divisors and Line Bundles
2.4 The Projective Space
2.5 Blow-ups
2.6 Differential Calculus on Complex Manifolds
3 Kahler Manifolds
3.1 Kahler Identities
3.2 Hodge Theory on Kahler Manifolds
3.3 Lefschetz Theorems
Appendix
3.A Formality of Compact Kahler Manifolds
3.B SUSY for Kahler Manifolds
3.C Hodge Structures
4 Vector Bundles
4.1 Hermitian Vector Bundles and Serre Duality
4.2 Connections
4.3 Curvature
4.4 Chern Classes
Appendix
4.A Levi-Civita Connection and Holonomy on Complex Manifolds
4.B Hermite-Einstein and Kahler-Einstein Metrics
5 Applications of Cohomology
5.1 Hirzebruch-Riemann-Roch Theorem
5.2 Kodaira Vanishing Theorem and Applications
5.3 Kodaira Embedding Theorem
Deformations of Complex Structures
6.1 The Maurer-Cartan Equation
6.2 General Results
Appendix
6.A dGBV-Algebras
A Hodge Theory on Differentiable Manifolds
B Sheaf Cohomology
References
Index
前言/序言
Complex geometry is a highly attractive branch of modern mathematics thathas witnessed many years of active and successful research and that has recently obtained new impetus from physicists interest in questions related tomirror symmetry. Due to its interactions with various other fields (differential,algebraic, and arithmetic geometry, but also string theory and conformal fieldtheory), it has become an area with many facets. Also, there are a number ofchallenging open problems which contribute to the subjects attraction. Themost famous among them is the Hodge conjecture, one of the seven one-milliondollar millennium problems of the Clay Mathematics Institute. So, it seemslikely that this area will fascinate new generations for many years to come.
Complex geometry, as presented in this book, studies the geometry of(mostly compact) complex manifolds. A complex manifold is a differentiablemanifold endowed with the additional datum of a complex structure which ismuch more rigid than the geometrical structures in differential geometry. Dueto this rigidity, one is often able to describe the geometry of complex manifoldsin very explicit terms. E.g. the important class of projective manifolds can, inprinciple, be described as zero sets of polynomials.
Yet, a complete classification of all compact complex manifolds is toomuch to be hoped for. Complex curves can be classified in some sense (in-volving moduli spaces etc.), but already the classification of complex surfacesis tremendously complicated and partly incomplete.
In this book we will concentrate on more restrictive types of complexmanifolds for which a rather complete theory is in store and which are alsorelevant in the applications. A prominent example are Calabi-Yau manifolds,which play a central role in questions related to mirror symmetry. Often,interesting complex manifolds are distinguished by the presence of specialRiemannian metrics. This will be one of the central themes throughout thistext. The idea is to study cases where the Riemannian and complex geometryon a differentiable manifold are not totally unrelated.
几何学的深邃之域:从欧几里得到黎曼的拓扑与结构探索 内容提要: 本书旨在带领读者进行一场跨越时空的几何学之旅,从古希腊的欧氏几何基础出发,逐步深入到近代数学对空间本质的全新理解。我们将探讨非欧几里得几何的诞生及其对经典认知的颠覆,聚焦于拓扑学的核心概念,并触及微分几何在描述复杂曲面和流形上的强大应用。全书强调几何直觉与严谨逻辑的结合,旨在构建一个清晰、全面的现代几何学图景,为理解物理学、现代拓扑乃至更抽象的数学结构打下坚实的基础。本书将避开复分析的特定领域,专注于实数域上的空间形态、度量和连续变换。 --- 第一章:欧氏空间的坚实基石与经典悖论 本章伊始,我们将回顾欧几里得几何的五大公设,特别是其第五公设(平行公设)在两千多年间所引发的深刻危机。我们将详细分析在保持其他四条公设不变的情况下,对第五公设进行否定或修改所必然导致的几何系统——非欧几何的预兆。 公理系统的完备性与独立性探究: 深入剖析希尔伯特公理化系统如何为欧氏几何提供一个更为严谨的逻辑框架。重点讨论点、线、平面之间的关系,以及顺序、分割和全等这些基本概念的公理化表达。 度量与刚体运动: 欧氏几何的标志在于其固有的距离和角度概念,这些概念是通过刚体运动(平移和旋转)来保持不变的。本节将严格定义欧氏距离公式,并探讨通过等距变换(Isometries)来刻画空间结构的方法。 几何直觉的局限性: 通过对高维欧氏空间的有限度可视化尝试,揭示人类直觉在处理超过三维空间时的局限性,从而引出研究抽象空间的必要性。 第二章:非欧几何的革命:空间的内在曲率 第五公设的叛逆催生了两个主要的非欧几何体系:罗巴切夫斯基几何(双曲几何)和黎曼几何(椭圆几何的早期形态)。本章将详细构建这些体系,理解它们与欧氏几何在基本性质上的根本区别。 双曲几何(罗巴切夫斯基/波雅伊): 重点讨论在平面上,过一点有无数条不与给定直线相交的直线(平行线)。我们将使用庞加莱圆盘模型和双曲面模型来可视化这种负曲率空间。分析双曲三角形的内角和恒小于 $pi$ 的惊人结论,及其对三角函数关系(如双曲正弦和余弦)的重构。 椭圆几何(球面几何): 作为正曲率空间的代表,球面几何中不存在平行线,任意两条“直线”(大圆)必然相交。分析球面三角形的内角和恒大于 $pi$ 的性质,以及地理学和天文学中球面几何的应用。 高斯的可展性理论与曲率的定义: 引入高斯“奇想”——著名的“绝妙定理”(Theorema Egregium)。该定理指出,高斯曲率仅由第一基本形式决定,而与空间嵌入的外部环境无关。这标志着曲率从依赖于嵌入空间的量,转变为空间自身的内在属性。 第三章:拓扑学的诞生:不变量与形变 本章将从关注长度、角度的度量几何,转向关注“连续性”和“形变”的拓扑学。拓扑学是对那些在连续形变(拉伸、弯曲,但不撕裂或粘合)下保持不变的性质的研究。 拓扑等价与同胚: 严格定义同胚(Homeomorphism)的概念,它代表了拓扑学中的“等价”。讨论杯子和甜甜圈(环面)为何是拓扑等价的,而球体和圆环面则不是。 拓扑不变量: 深入探讨能够区分不同拓扑空间的量。 连通性: 讨论路径连通性与道路连通性的区别。 洞的数量(亏格/Genus): 引入亏格的概念,作为区分二维流形拓扑类型的主要拓扑不变量。 欧拉示性数(Euler Characteristic): 介绍欧拉示性数 $chi = V - E + F$ 在多面体上的计算,并将其推广到任意紧致可定向的二维流形,展示它在拓扑分类中的核心作用。 紧致性与分离公理: 介绍拓扑空间理论中的两个关键性质:紧致性(Compactness)对连续函数最大值存在性的保证,以及分离公理(如Hausdorff性质)对局部结构描述的必要性。 第四章:流形的概念与微分几何的初步接触 为了在光滑的曲面上进行微积分运算,我们需要一个局部看起来像欧氏空间的数学对象——流形。本章将建立起从局部到整体的桥梁。 $n$ 维流形的定义: 形式化定义一个拓扑流形:一个Hausdorff空间,局部上同胚于 $mathbb{R}^n$ 的空间。讨论切线空间的概念,它是流形上每一点的“局部欧氏近似”。 光滑结构与坐标图册: 解释为什么仅仅有拓扑结构是不够的,我们需要“光滑结构”(即坐标变换是光滑的)才能在流形上进行微分运算。引入图册(Atlas)和转移映射(Transition Maps)的概念。 度量张量与黎曼流形: 在光滑流形上引入度量张量的概念,它是一个定义在每一点切空间上的正定二次型。黎曼流形即是配备了度量张量的光滑流形。 测地线(Geodesics): 讨论测地线是流形上两点之间“最短路径”的推广。在局部,测地线可以看作是无加速度的运动轨迹,其定义依赖于度量张量所导出的连接系数(Christoffel符号)。 第五章:从曲率到几何的统一:黎曼几何的广阔视野 本章将超越二维曲面,进入高维黎曼流形的领域,探讨曲率如何影响空间中的几何性质。 黎曼曲率张量: 介绍黎曼曲率张量的精确定义,它量化了平行移动(在流形上“携带”向量)时,向量旋转偏离初始方向的程度。曲率张量是描述流形弯曲程度的最精细的内在工具。 截面曲率与丰富性: 讨论截面曲率(Sectional Curvature),它是在流形上任意二维平面上测得的高斯曲率的推广。通过截面曲率的正负,我们可以直观地理解空间的局部几何行为。 测地线的发散与时空结构: 探讨在不同曲率空间中,邻近测地线的行为差异(例如,在正曲率空间中会向内收缩,在负曲率空间中则会迅速发散)。这为理解广义相对论中时空弯曲的几何后果提供了必要的数学框架。 --- 本书的特色与读者对象: 本书结构清晰,逻辑递进自然,力求在保持数学严谨性的同时,激发读者的几何洞察力。它不依赖于复杂的代数工具,而是通过构造性论证和模型可视化来深化理解。本书特别适合: 1. 高等数学和物理学专业学生,作为他们进入微分几何、广义相对论或高维拓扑学课程的预备读物。 2. 对空间结构和连续性本质有深刻好奇心的数学爱好者,他们希望超越传统欧氏几何的界限,探索现代几何学的核心概念。 3. 需要回顾或系统学习非欧几何和黎曼几何基础的科研人员。 通过对欧氏空间、非欧空间、拓扑不变量以及黎曼流形的系统性考察,读者将对“空间”这一核心概念获得一个更为丰富和精确的理解。