Euclidean Geometry / 1: |
Preliminaries / 1.1: |
Distance Geometry / 1.2: |
A Basic Formula / 1.2.1: |
The Length of a Path / 1.2.2: |
The First Variation Formula and Application to Billiards / 1.2.3: |
Plane Curves / 1.3: |
Length / 1.3.1: |
Curvature / 1.3.2: |
Global Theory of Closed Plane Curves / 1.4: |
"Obvious" Truths About Curves Which are Hard to Prove / 1.4.1: |
The Four Vertex Theorem / 1.4.2: |
Convexity with Respect to Arc Length / 1.4.3: |
Umlaufsatz with Corners / 1.4.4: |
Heat Shrinking of Plane Curves / 1.4.5: |
Arnol'd's Revolution in Plane Curve Theory / 1.4.6: |
The Isoperimetric Inequality for Curves / 1.5: |
The Geometry of Surfaces Before and After Gauß / 1.6: |
Inner Geometry: a First Attempt / 1.6.1: |
Looking for Shortest Curves: Geodesics / 1.6.2: |
The Second Fundamental Form and Principal Curvatures / 1.6.3: |
The Meaning of the Sign of K / 1.6.4: |
Global Surface Geometry / 1.6.5: |
Minimal Surfaces / 1.6.6: |
The Hartman-Nirenberg Theorem for Inner Flat Surfaces / 1.6.7: |
The Isoperimetric Inequality in <$>{\op E}^3<$> à la Gromov / 1.6.8: |
Notes / 1.6.8.1: |
Generic Surfaces / 1.7: |
Heat and Wave Analysis in <$>{\op E}^2<$> / 1.8: |
Planar Physics / 1.8.1: |
Bibliographical Note / 1.8.1.1: |
Why the Eigenvalue Problem? / 1.8.2: |
Minimax / 1.8.3: |
Shape of a Drum / 1.8.4: |
A Few Direct Problems / 1.8.4.1: |
The Faber-Krahn Inequality / 1.8.4.2: |
Inverse Problems / 1.8.4.3: |
Heat / 1.8.5: |
Eigenfunctions / 1.8.5.1: |
Relations Between the Two Spectra / 1.8.6: |
Heat and Waves in <$>{\op E}^3<$>, <$>{\op E}^d<$> and on the Sphere / 1.9: |
Euclidean Spaces / 1.9.1: |
Spheres / 1.9.2: |
Billiards in Higher Dimensions / 1.9.3: |
The Wave Equation Versus the Heat Equation / 1.9.4: |
Transition / 2: |
Surfaces from Gauß to Today / 3: |
Gauß / 3.1: |
Theorema Egregium / 3.1.1: |
The First Proof of Gauß's Theorema Egregium; the Concept of ds2 / 3.1.1.1: |
Second Proof of the Theorema Egregium / 3.1.1.2: |
The Gauß-Bonnet Formula and the Rodrigues-Gauß Map / 3.1.2: |
Parallel Transport / 3.1.3: |
Inner Geometry / 3.1.4: |
Alexandrov's Theorems / 3.2: |
Angle Corrections of Legendre and Gauß in Geodesy / 3.2.1: |
Cut Loci / 3.3: |
Global Surface Theory / 3.4: |
Bending Surfaces / 3.4.1: |
Bending Polyhedra / 3.4.1.1: |
Bending and Wrinkling with Little Smoothness / 3.4.1.2: |
Mean Curvature Rigidity of the Sphere / 3.4.2: |
Negatively Curved Surfaces / 3.4.3: |
The Willmore Conjecture / 3.4.4: |
The Global Gauß-Bonnet Theorem for Surfaces / 3.4.5: |
The Hopf Index Formula / 3.4.6: |
Riemann's Blueprints / 4: |
Smooth Manifolds / 4.1: |
Introduction / 4.1.1: |
The Need for Abstract Manifolds / 4.1.2: |
Examples / 4.1.3: |
Submanifolds / 4.1.3.1: |
Products / 4.1.3.2: |
Lie Groups / 4.1.3.3: |
Homogeneous Spaces / 4.1.3.4: |
Grassmannians over Various Algebras / 4.1.3.5: |
Gluing / 4.1.3.6: |
The Classification of Manifolds / 4.1.4: |
Surfaces / 4.1.4.1: |
Higher Dimensions / 4.1.4.2: |
Embedding Manifolds in Euclidean Space / 4.1.4.3: |
Calculus on Manifolds / 4.2: |
Tangent Spaces and the Tangent Bundle / 4.2.1: |
Differential Forms and Exterior Calculus / 4.2.2: |
Examples of Riemann's Definition / 4.3: |
Riemann's Definition / 4.3.1: |
Hyperbolic Geometry / 4.3.2: |
Products, Coverings and Quotients / 4.3.3: |
Coverings / 4.3.3.1: |
Symmetric Spaces / 4.3.4: |
Classification / 4.3.5.1: |
Rank / 4.3.5.2: |
Riemannian Submersions / 4.3.6: |
Gluing and Surgery / 4.3.7: |
Gluing of Hyperbolic Surfaces / 4.3.7.1: |
Higher Dimensional Gluing / 4.3.7.2: |
Classical Mechanics / 4.3.8: |
The Riemann Curvature Tensor / 4.4: |
Discovery and Definition / 4.4.1: |
The Sectional Curvature / 4.4.2: |
Standard Examples / 4.4.3: |
Constant Sectional Curvature / 4.4.3.1: |
Projective Spaces <$>{\op KP}^n<$> / 4.4.3.2: |
Hypersurfaces in Euclidean Space / 4.4.3.3: |
A Naive Question: Does the Curvature Determine the Metric? / 4.5: |
Any Dimension / 4.5.1: |
Abstract Riemannian Manifolds / 4.6: |
Isometrically Embedding Surfaces in <$>{\op E}^3<$> / 4.6.1: |
Local Isometric Embedding of Surfaces in <$>{\op E}^3<$> / 4.6.2: |
Isometric Embedding in Higher Dimensions / 4.6.3: |
A One Page Panorama / 5: |
Metric Geometry and Curvature / 6: |
First Metric Properties / 6.1: |
Local Properties / 6.1.1: |
Hopf-Rinow and de Rham Theorems / 6.1.2: |
Convexity and Small Balls / 6.1.2.1: |
Totally Geodesic Submanifolds / 6.1.4: |
Center of Mass / 6.1.5: |
Examples of Geodesics / 6.1.6: |
First Technical Tools / 6.1.7: |
Second Technical Tools / 6.3: |
Exponential Map / 6.3.1: |
Space Forms / 6.3.1.1: |
Nonpositive Curvature / 6.3.3: |
Triangle Comparison Theorems / 6.4: |
Bounded Sectional Curvature / 6.4.1: |
Ricci Lower Bound / 6.4.2: |
Philosophy Behind These Bounds / 6.4.3: |
Injectivity, Convexity Radius and Cut Locus / 6.5: |
Definition of Cut Points and Injectivity Radius / 6.5.1: |
Klingenberg and Cheeger Theorems / 6.5.2: |
Convexity Radius / 6.5.3: |
Cut Locus / 6.5.4: |
Blaschke Manifolds / 6.5.5: |
Geometric Hierarchy / 6.6: |
The Geometric Hierarchy / 6.6.1: |
Rank 1 Symmetric Spaces / 6.6.1.1: |
Measure Isotropy / 6.6.1.3: |
Negatively Curved Space Forms in Three and Higher Dimensions / 6.6.1.4: |
Mostow Rigidity / 6.6.2.2: |
Classification of Arithmetic and Nonarithmetic Negatively Curved Space Forms / 6.6.2.3: |
Volumes of Negatively Curved Space Forms / 6.6.2.4: |
Higher Rank Symmetric Spaces / 6.6.3: |
Superrigidity / 6.6.4.1: |
Volumes and Inequalities on Volumes of Cycles / 6.6.5: |
Curvature Inequalities / 7.1: |
Bounds on Volume Elements and First Applications / 7.1.1: |
The Canonical Measure / 7.1.1.1: |
Volumes of Standard Spaces / 7.1.1.2: |
The Isoperimetric Inequality for Spheres / 7.1.1.3: |
Sectional Curvature Upper Bounds / 7.1.1.4: |
Ricci Curvature Lower Bounds / 7.1.1.5: |
Isoperimetric Profile / 7.1.2: |
Definition and Examples / 7.1.2.1: |
The Gromov-Bérard-Besson-Gallot Bound / 7.1.2.2: |
Nonpositive Curvature on Noncompact Manifolds / 7.1.2.3: |
Curvature Free Inequalities on Volumes of Cycles / 7.2: |
Curves in Surfaces / 7.2.1: |
Loewner, Pu and Blatter-Bavard Theorems / 7.2.1.1: |
Higher Genus Surfaces / 7.2.1.2: |
The Sphere / 7.2.1.3: |
Homological Systoles / 7.2.1.4: |
Inequalities for Curves / 7.2.2: |
The Problem, and Standard Manifolds / 7.2.2.1: |
Filling Volume and Filling Radius / 7.2.2.2: |
Gromov's Theorem and Sketch of the Proof / 7.2.2.3: |
Higher Dimensional Systoles: Systolic Freedom Almost Everywhere / 7.2.3: |
Embolic Inequalities / 7.2.4: |
The Unit Tangent Bundle / 7.2.4.1: |
The Core of the Proof / 7.2.4.3: |
Croke's Three Results / 7.2.4.4: |
Infinite Injectivity Radius / 7.2.4.5: |
Using Embolic Inequalities / 7.2.4.6: |
Transition: The Next Two Chapters / 8: |
Spectral Geometry and Geodesic Dynamics / 8.1: |
Why are Riemannian Manifolds So Important? / 8.2: |
Positive Versus Negative Curvature / 8.3: |
Spectrum of the Laplacian / 9: |
History / 9.1: |
Motivation / 9.2: |
Setting Up / 9.3: |
X definition / 9.3.1: |
The Hodge Star / 9.3.2: |
Facts / 9.3.3: |
Heat, Wave and Schrodinger Equations / 9.3.4: |
The Principle / 9.4: |
An Application / 9.4.2: |
Some Extreme Examples / 9.5: |
Square Tori, Alias Several Variable Fourier Series / 9.5.1: |
Other Flat Tori / 9.5.2: |
<$>{\op KP}^n<$> / 9.5.3: |
Other Space Forms / 9.5.5: |
Current Questions / 9.6: |
Direct Questions About the Spectrum / 9.6.1: |
Direct Problems About the Eigenfunctions / 9.6.2: |
Inverse Problems on the Spectrum / 9.6.3: |
First Tools: The Heat Kernel and Heat Equation / 9.7: |
The Main Result / 9.7.1: |
Great Hopes / 9.7.2: |
The Heat Kernel and Ricci Curvature / 9.7.3: |
The Wave Equation: The Gaps / 9.8: |
The Wave Equation: Spectrum & Geodesic Flow / 9.9: |
The First Eigenvalue / 9.10: |
λ1 and Ricci Curvature / 9.10.1: |
Cheeger's Constant / 9.10.2: |
λ1 and Volume; Surfaces and Multiplicity / 9.10.3: |
Kähler Manifolds / 9.10.4: |
Results on Eigenfunctions / 9.11: |
Distribution of the Eigenfunctions / 9.11.1: |
Volume of the Nodal Hypersurfaces / 9.11.2: |
Distribution of the Nodal Hypersurfaces / 9.11.3: |
The Nature of the Image / 9.12: |
Inverse Problems: Nonuniqueness / 9.12.2: |
Inverse Problems: Finiteness, Compactness / 9.12.3: |
Uniqueness and Rigidity Results / 9.12.4: |
Vignéras Surfaces / 9.12.4.1: |
Special Cases / 9.13: |
Riemann Surfaces / 9.13.1: |
Scars / 9.13.2: |
The Spectrum of Exterior Differential Forms / 9.14: |
Geodesic Dynamics / 10: |
Some Well Understood Examples / 10.1: |
Surfaces of Revolution / 10.2.1: |
Zoll Surfaces / 10.2.1.1: |
Weinstein Surfaces / 10.2.1.2: |
Ellipsoids and Morse Theory / 10.2.2: |
Flat and Other Tori: Influence of the Fundamental Group / 10.2.3: |
Flat Tori / 10.2.3.1: |
Manifolds Which are not Simply Connected / 10.2.3.2: |
Tori, not Flat / 10.2.3.3: |