內容簡介
This book, which is in two parts, provides an introduction to the theory of vector- valued functions on Euclidean space. We focus on four main objects of study and in addition consider the interactions between these. Volume I is devoted to differentiation. Differentiable functions on Rn come first, in Chapters 1 through 3. Next, differentiable manifolds embedded in R are discussed, in Chapters 4 and 5. In Volume 11 we take up integration. Chapter 6 deals with the theory of n-dimensional integration over R. Finally, in Chapters 7 and 8 lower-dimensional integration over submanifolds of Rn is developed; particular attention is paid to vector analysis and the theory of differential forms, which are treated independently from each other. Generally speaking, the emphasis is on geometric aspects of analysis rather than on matters belonging to functional analysis.
內頁插圖
目錄
Volume Ⅰ
Preface
Acknowledgments
Introduction
1 Continuity
1.1 Inner product and norm
1.2 Open and closed sets
1.3 Limits and continuous mappings
1.4 Composition of mappings
1.5 Homeomorphisms
1.6 Completeness
1.7 Contractions
1.8 Compactness and uniform continuity
1.9 Connectedness
2 Differentiation
2.1 Linear mappings
2.2 Differentiable mappings
2.3 Directional and partial derivatives
2.4 Chain rule
2.5 Mean Value Theorem
2.6 Gradient
2.7 Higher-order derivatives
2.8 Taylor's formula
2.9 Critical points
2.10Commuting limit operations
3 Inverse Function and Implicit Function Theorems
3.1 Diffeomorphisms
3.2 Inverse Function Theorems
3.3 Applications oflnverse Function Theorems
3.4 Implicitly defined mappings
3.5 Implicit Function Theorem
3.6 Applications of the Implicit Function Theorem
3.7 Implicit and Inverse Function Theorems on C
4 Manifolds
4.1 Introductory remarks
4.2 Manifolds
4.3 Immersion Theorem
4.4 Examples of immersions
4.5 Submersion Theorem
4.6 Examples of submersions
4.7 Equivalent definitions of manifold
4.8 Morse's Lemma
5 Tangent Spaces
5.1 Definition of tangent space
5.2 Tangent mapping
5.3 Examples of tangent spaces
5.4 Method of Lagrange multipliers
5.5 Applications of the method of multipliers
5.6 Closer investigation of critical points
5.7 Gaussian curvature of surface
5.8 Curvature and torsion of curve in R3
5.9 One-parameter groups and infinitesimal generators
5.10 Linear Lie groups and their Lie algebras
5.11 Transversality
Exercises
Review Exercises
Exercises for Chapter 1
Exercises for Chapter 2
Exercises for Chapter 3
Exercises for Chapter 4
Exercises for Chapter 5
Notation
Index
Volume Ⅱ
Preface
Acknowledgments
Introduction
6 Integration
6.1 Rectangles
6.2 Riemann integrability
6.3Jordan measurability
6.4 Successive integration
6.5 Examples of successive integration
6.6 Change of Variables Theorem: formulation and examples
6.7 Partitions of unity
6.8 Approximation of Riemann integrable functions
6.9 Proof of Change of Variables Theorem
6.10 Absolute Riemann integrability
6.11 Application of integration: Fourier transformation
6.12 Dominated convergence
6.13 Appendix: two other proofs of Change of Variables Theorem
7 Integration over Submanifolds
7.1 Densities and integration with respect to density
7.2 Absolute Riemann integrability with respect to density
7.3 Euclidean d-dimensional density
7.4 Examples of Euclidean densities
7.5 Open sets at one side of their boundary
7.6 Integration of a total derivative
7.7 Generalizations of the preceding theorem
7.8 Gauss' Divergence Theorem
7.9 Applications of Gauss' Divergence Theorem
8 Oriented Integration
8.1 Line integrals and properties of vector fields
8.2 Antidifferentiation
8.3 Green's and Cauchy's Integral Theorems
8.4 Stokes' Integral Theorem
8.5 Applications of Stokes' Integral Theorem
8.6 Apotheosis: differential forms and Stokes' Theorem .
8.7 Properties of differential forms
8.8 Applications of differential forms
8.9 Homotopy Lemma
8.10 Poincare's Lemma
8.11 Degree of mapping
Exercises
Exercises for Chapter 6
Exercises for Chapter 7
Exercises for Chapter 8
Notation
Index
前言/序言
拓撲學基礎:從點集到函數空間 本書旨在為讀者建立一套堅實的拓撲學基礎,重點在於深入理解點集拓撲(General Topology)的核心概念、定理及其在現代數學分析中的應用。全書以嚴謹的數學語言和清晰的邏輯結構組織,力求使讀者不僅掌握定義和定理,更能洞察其背後的幾何直覺與分析意義。 第一部分:度量空間與基礎結構 本書的開篇聚焦於度量空間(Metric Spaces),這是分析學中最基本的結構載體。 第一章:度量與拓撲的起源 我們首先引入度量(Metric)的概念,定義距離函數必須滿足的四個基本性質:非負性、同一性、對稱性與三角不等式。隨後,我們探討如何從一個度量空間自然地導齣拓撲結構。開球(Open Ball)作為拓撲的基礎元素被詳細討論,並推廣至開集(Open Set)的定義。本章將對開集族的性質進行詳盡的論證,包括任意並集和有限交集的性質。 緊接著,我們引入閉集(Closed Set)的對偶概念,並闡述閉集是開集的補集的定義。通過對鄰域(Neighborhood)概念的細緻分析,我們展示瞭如何用鄰域來重新定義拓撲結構,從而建立拓撲空間(Topological Space)的概念。 第二章:基礎拓撲概念的深化 本章深入探討拓撲空間的內在結構。我們定義瞭內點(Interior Point)、外點(Exterior Point)和邊界點(Boundary Point),並引入瞭閉包(Closure)和開核(Interior)的正式定義。特彆強調瞭閉包 $ar{A} = A cup A'$ 以及 $ ext{Int}(A) = A setminus partial A$ 等恒等式。 隨後,本書詳細討論瞭稠密子集(Dense Subset)的概念,這對於理解函數的逼近性至關重要。我們考察瞭可數性(Countability)的概念,包括可數集和可數緊集,並初步引入瞭第一可數公理(First Countability Axiom)和第二可數公理(Second Countability Axiom),解釋瞭它們在利用點列(Sequences)和可數基(Countable Basis)進行拓撲分析時的重要性。 第二部分:連續性、收斂與連接性 在建立瞭基礎的拓撲框架後,我們轉嚮分析學中最為核心的概念:連續性和收斂性,並引入瞭連接性來描述空間的“整體性”。 第三章:連續函數與拓撲同胚 本章的核心是連續函數的拓撲定義。我們從度量空間中的 $epsilon-delta$ 語言齣發,展示瞭如何在一般拓撲空間中用開集的像來定義連續性,即$f: X o Y$ 是連續的當且僅當對於 $Y$ 中任意開集 $V$,其原像 $f^{-1}(V)$ 是 $X$ 中的開集。 我們隨後探討瞭更強的概念:開映射(Open Map)和閉映射(Closed Map)。拓撲同胚(Homeomorphism)被定義為既連續又具有連續逆的映射,它衡量的是兩個拓撲空間在結構上的等價性。本章通過大量實例說明瞭拓撲同胚在幾何形狀識彆中的應用。 第四章:收斂性與濾子(Filters) 在度量空間中,點列收斂是主要工具,但在更一般的拓撲空間中,點列的概念可能不足夠。我們首先迴顧瞭點列收斂的拓撲定義。 隨後,本書引入瞭更強大的工具——濾子(Filters)和濾子收斂。濾子提供瞭處理“網”(Nets)的代數框架,使得在非度量化空間中也能完整描述收斂概念。我們論證瞭拓撲空間中緊緻性、點列緊緻性與濾子收斂之間的深刻聯係。 第五章:連通性與分離公理 連通性(Connectedness)是描述拓撲空間“不被分割”性質的重要概念。我們定義瞭連通空間,並證明瞭連續函數的像保持連通性。路徑連通性(Path-Connectedness)作為一種更強的連通性概念被提齣,並探討瞭在 $mathbb{R}^n$ 中兩者等價的原因。 本書的後半部分著重於拓撲空間的“光滑度”或“分離程度”,即分離公理(Separation Axioms)。我們係統地定義並區分瞭 $T_1, T_2$ (豪斯多夫, Hausdorff), $T_3, T_4$ (正則與完全正則) 公理。特彆強調瞭豪斯多夫空間的重要性,它保證瞭極限點的唯一性,是後續函數分析的必要前提。 第三部分:緊緻性與完備性 緊緻性(Compactness)和完備性(Completeness)是泛函分析和微分拓撲學的兩大支柱。 第六章:緊緻性及其等價命題 緊緻性被定義為開有限覆蓋的性質。我們首先證明瞭在 $mathbb{R}^n$ 上的 Heine-Borel 定理,這是緊緻性的經典體現。隨後,本書詳細論證瞭在一般的拓撲空間中,緊緻性與點列緊緻性、可數緊緻性之間的關係,並明確指齣在任意豪斯多夫空間中,緊緻性等價於點列緊緻性。 緊緻性在分析中的核心應用是:連續函數在緊集上能達到其最大值和最小值。本章還討論瞭緊集的任意子集的緊緻性,以及緊集族(Compact Collections)的性質。 第七章:完備性與巴拿赫不動點定理 完備性關注的是空間中柯西序列的收斂性。我們定義瞭柯西序列(Cauchy Sequence),並引入瞭完備度量空間的概念。 本章的重點在於巴拿赫不動點定理(Banach Fixed-Point Theorem),也稱壓縮映射定理。我們詳細推導瞭該定理的條件、結論和唯一性,並展示瞭它在求解常微分方程初值問題和迭代方法中的直接應用。 最後,我們探討瞭完備化的過程(Completion),即如何將任意度量空間嵌入到一個最小的完備度量空間中(如實數軸對有理數的完備化)。 總結與展望 全書在結構上層層遞進,從最直觀的度量概念齣發,逐步抽象到一般拓撲空間,最終聚焦於保證分析工具(如收斂性、連續性、極限存在性)有效性的關鍵結構屬性——緊緻性與完備性。本書為學習更高階的泛函分析、微分幾何以及概率論中的測度論奠定瞭不可或缺的理論基礎。