توضیحاتی در مورد کتاب :
جریان های هندسی بیرونی با یک زیرمنیفولد در حال تکامل در یک فضای محیطی با سرعت تعیین شده توسط انحنای بیرونی آن مشخص می شوند. هدف این کتاب ارائه مقدمه ای گسترده برای چند مورد از برجسته ترین جریان های بیرونی، یعنی جریان کوتاه شدن منحنی، جریان انحنای متوسط، جریان انحنای گاوس، جریان انحنای متوسط معکوس، و جریان های کاملا غیر خطی از انحنای متوسط و نوع انحنای متوسط معکوس. نویسندگان تکنیکها و رفتارهایی را که اغلب در مطالعه این جریانها (و سایر جریانها) بروز میکنند، برجسته میکنند. برای نشان دادن کاربرد وسیع تکنیکهای توسعهیافته، آنها همچنین کلاسهای کلی جریانهای انحنای کاملا غیرخطی را در نظر میگیرند. این کتاب در سطح دانشجویی نوشته شده است که دروس پایه هندسه دیفرانسیل را گذرانده و با معادلات دیفرانسیل جزئی آشنایی دارد. همچنین در نظر گرفته شده است که به عنوان مرجعی برای متخصصان مفید باشد. به طور کلی، نویسندگان شواهد دقیق ارائه میکنند، اگرچه برای برخی از نتایج تخصصیتر، آنها ممکن است فقط ایدههای اصلی را ارائه دهند. در چنین مواردی برای اثبات کامل مراجع ارائه می کنند. بررسی مختصری از موضوعات اضافی با ارجاعات گسترده را می توان در یادداشت ها و تفسیر انتهای هر فصل یافت.
فهرست مطالب :
Contents
Preface
A Guide for the Reader
The heat equation (Chapter 1)
Curve shortening flow (Chapters 2–4)
Mean curvature flow (Chapters 5–14)
Gauß curvature flows (Chapters 15–17)
Fully nonlinear curvature flows (Chapters 18–20)
Acknowledgments
Suggested Course Outlines
Notation and Symbols
Chapter 1. The Heat Equation
§1.1. Introduction
§1.2. Gradient flow
§1.3. Invariance properties
1.3.1. Generating solutions from symmetries
1.3.2. Invariant solutions
§1.4. The maximum principle
§1.5. Well-posedness
§1.6. Asymptotic behavior
§1.7. The Bernstein method
§1.8. The Harnack inequality
§1.9. Further monotonicity formulae
1.9.1. The Nash entropy
1.9.2. Weighted monotonicity formulae
1.9.3. Semilinear heat equations
§1.10. Sharp gradient estimates
§1.11. Notes and commentary
1.11.1. The Omori–Yau maximum principle
1.11.2. Sturm’s theorem
1.11.3. The differential Harnack inequality
1.11.4. Ancient solutions
1.11.5. The heat equation on Riemannian manifolds
§1.12. Exercises
Chapter 2. Introduction to Curve Shortening
§2.1. Basic geometric theory of planar curves
2.1.1. Immersed, embedded, and closed curves
2.1.2. Arc length, tangency, and normalcy
2.1.3. Curvature
2.1.4. Round circles
2.1.5. The normal angle
2.1.6. Arc length element, rotation index
§2.2. Curve shortening flow
§2.3. Graphs of functions
2.3.1. Grim Reaper solution
§2.4. The support function
§2.5. Short-time existence
§2.6. Smoothing
§2.7. Global existence
§2.8. Notes and commentary
§2.9. Exercises
Chapter 3. The Gage–Hamilton–Grayson Theorem
§3.1. The avoidance principle
§3.2. Preserving embeddedness
§3.3. Huisken’s distance comparison estimate
§3.4. A curvature bound by distance comparison
§3.5. Grayson’s theorem
§3.6. Singularities of immersed solutions
§3.7. Notes and commentary
§3.8. Exercises
Chapter 4. Self-Similar and Ancient Solutions
§4.1. Invariance properties
§4.2. Self-similar solutions
§4.3. Monotonicity formulae
4.3.1. Isoperimetric ratio. The isoperimetric inequality
4.3.2. Differential Harnack estimate
4.3.3. Entropy monotonicity
4.3.4. A sketch of the Gage–Hamilton proof that convex embeddedcurves converge to round points
4.3.5. Huisken’s monotonicity formula
4.3.6. Monotonicity via Sturm’s theorem
§4.4. Ancient solutions
4.4.1. The hairclip solution
4.4.2. The paperclip solution
§4.5. Classification of convex ancient solutions on S^1
§4.6. Notes and commentary
§4.7. Exercises
Chapter 5. Hypersurfaces in Euclidean Space
§5.1. Parametrized hypersurfaces
§5.2. Alternative representations of hypersurfaces
5.2.1. Graphs of functions
5.2.2. Level sets at regular values
5.2.3. Starshaped hypersurfaces
5.2.4. Convex hypersurfaces
§5.3. Dynamical properties
5.3.1. Geometry on the pullback bundle
5.3.2. Evolving orthonormal frames
5.3.3. First variation of area and volume
§5.4. Curvature flows
5.4.1. The linearized flow
5.4.2. Local coordinate calculations for flows
§5.5. Notes and commentary
§5.6. Exercises
Chapter 6. Introduction to Mean Curvature Flow
§6.1. The mean curvature flow
6.1.1. Explicit solutions to the mean curvature flow
§6.2. Invariance properties and self-similar solutions
6.2.1. Translators
6.2.2. Shrinkers and expanders
6.2.3. Rotators
§6.3. Evolution equations
6.3.1. The gradient flow of the area functional
6.3.2. Normalized mean curvature flow
§6.4. Short-time existence
6.4.1. Invariance under diffeomorphisms
6.4.2. Short-time existence
§6.5. The maximum principle
6.5.1. Maximum principle for scalars
6.5.2. A maximum principle for tensors
§6.6. The avoidance principle
§6.7. Preserving embeddedness
§6.8. Long-time existence
§6.9. Weak solutions
6.9.1. The Brakke flow
6.9.2. The level set flow
6.9.3. The viscosity approach
6.9.4. The shadow flow of Sáez Trumper and Schnürer
6.9.5. Mean curvature flow with surgery
§6.10. Notes and commentary
6.10.1. Maximum principles
6.10.2. Constrained mean curvature flows
6.10.3. Well-posedness
6.10.4. Blow-up of the mean curvature
6.10.5. The compact-open C^k topology
6.10.6. Regularity of the level set flow
6.10.7. Mean curvature flow of soap film clusters
§6.11. Exercises
Chapter 7. Mean Curvature Flow of Entire Graphs
§7.1. Introduction
§7.2. Preliminary calculations
§7.3. The Dirichlet problem
§7.4. A priori height and gradient estimates
§7.5. Local a priori estimates for the curvature
§7.6. Proof of Theorem 7.1
§7.7. Convergence to self-similarly expanding solutions
§7.8. Self-similarly shrinking entire graphs
§7.9. Notes and commentary
§7.10. Exercises
Chapter 8. Huisken’s Theorem
§8.1. Pinching is preserved
§8.2. Pinching improves: The roundness estimate
§8.3. A gradient estimate for the curvature
§8.4. Huisken’s theorem
8.4.1. Convergence to a point
8.4.2. Estimates in C^0 after rescalling
8.4.3. Estimates in C^1 after rescaling
8.4.4. Estimates in C^∞ after rescaling
§8.5. Regularity of the arrival time
§8.6. Huisken’s theorem via width pinching
§8.7. Notes and commentary
8.7.1. Mean curvature flow in the sphere
8.7.2. Mean curvature flow in Riemannian ambient spaces
8.7.3. High-codimension mean curvature flow
8.7.4. Free boundary mean curvature flow
§8.8. Exercises
Chapter 9. Mean Convex Mean Curvature Flow
§9.1. Singularity formation
9.1.1. The standard neckpinch
9.1.2. The degenerate neckpinch
§9.2. Preserving pinching conditions
§9.3. Pinching improves: Convexity and cylindrical estimates
§9.4. A natural class of initial data
§9.5. A gradient estimate for the curvature
§9.6. Notes and commentary
§9.7. Exercises
Chapter 10. Monotonicity Formulae
§10.1. Huisken’s monotonicity formula
10.1.1. Pointwise monotonicity formula
10.1.2. A maximum principle for noncompact solutions
10.1.3. Local area bounds
§10.2. Hamilton’s Harnack estimate
10.2.1. The Harnack estimate as the nonnegativity of a quadratic
10.2.2. Saturation by expanding self-similar solutions
10.2.3. The Harnack calculation
10.2.4. The Harnack maximum principle argument
10.2.5. Convex eternal solutions
10.2.6. Space-time formulation of Hamilton’s Harnack estimate
10.2.7. Concavity of the arrival time
§10.3. Notes and commentary
10.3.1. Huisken’s monotonicity formula for Brakke flows
10.3.2. General monotonicity formulae
10.3.3. Huisken’s monotonicity formula for mean curvature flow ingeneral ambient spaces
10.3.4. Ecker’s local monotonicity formula
10.3.5. Monotonicity formula for free boundary mean curvatureflow
10.3.6. Smockzyk’s Harnack estimate for flows with speed f(H)
10.3.7. Harnack estimates for fully nonlinear flows
§10.4. Exercises
Chapter 11. Singularity Analysis
§11.1. Local uniform convergence of mean curvature flows
11.1.1. Hypersurfaces with bounded geometry
11.1.2. Mean curvature flows with bounded curvature
§11.2. Neck detection
§11.3. The Brakke–White regularity theorem
§11.4. Huisken’s theorem revisited
11.4.1. Proper hypersurfaces with pinched principal curvatures
§11.5. The structure of singularities
11.5.1. Singularity models for type-I singularities
11.5.2. The normalized flow about type-I singularities
11.5.3. Singularity models for type-II singularities
11.5.4. Tangent flows are shrinkers
11.5.5. Conjectures on singularity formation in mean curvature flow
11.5.6. Mean curvature flow with surgery
11.5.7. Piecewise smooth mean curvature flow
§11.6. Notes and commentary
11.6.1. A local compactness theorem
11.6.2. A local Brakke–White regularity theorem
11.6.3. Curvature pinching and compactness
11.6.4. Generic singularities and uniqueness of tangent flows
11.6.5. Singularities in free boundary mean curvature flow
§11.7. Exercises
Chapter 12. Noncollapsing
§12.1. The inscribed and exscribed curvatures
§12.2. Differential inequalities for the inscribed and exscribed curvatures
12.2.1. Simons-type differential inequalities
§12.3. The Gage–Hamilton and Huisken theorems via noncollapsing
§12.4. The Haslhofer–Kleiner curvature estimate
§12.5. Notes and commentary
§12.6. Exercises
Chapter 13. Self-Similar Solutions
§13.1. Shrinkers — an introduction
§13.2. The Gaußian area functional
13.2.1. Differential identities
§13.3. Mean convex shrinkers
§13.4. Compact embedded self-shrinking surfaces
13.4.1. Compact, embedded shrinkers of genus 0
13.4.2. Compact embedded shrinkers of higher genus
§13.5. Translators — an introduction
§13.6. The Dirichlet problem for graphical translators
§13.7. Cylindrical translators
§13.8. Rotational translators
§13.9. The convexity estimates of Spruck, Sun, and Xiao
§13.10. Asymptotics
§13.11. X.-J. Wang’s dichotomy
§13.12. Rigidity of the bowl soliton
§13.13. Flying wings
§13.14. Bowloids
§13.15. Notes and commentary
13.15.1. Classification of shrinkers
13.15.2. Open problems related to shrinkers
13.15.3. Classification of translators
13.15.4. Open problems related to translators
13.15.5. Expanders
13.15.6. Self-similar solutions to other flows
§13.16. Exercises
Chapter 14. Ancient Solutions
§14.1. Rigidity of the shrinking sphere
§14.2. A convexity estimate
§14.3. A gradient estimate for the curvature
§14.4. Asymptotics
§14.5. X.-J. Wang’s dichotomy
§14.6. Ancient solutions to curve shortening flow revisited
§14.7. Ancient ovaloids
§14.8. Ancient pancakes
§14.9. Notes and commentary
14.9.1. Classification of ancient solutions
14.9.2. Ancient solutions to further extrinsic curvature flows
14.9.3. Open problems related to ancient solutions
§14.10. Exercises
Chapter 15. Gauß Curvature Flows
§15.1. Invariance properties and self-similar solutions
15.1.1. Homothetic solutions
§15.2. Basic evolution equations
§15.3. Chou’s long-time existence theorem
15.3.1. A parabolic Monge–Ampère equation
15.3.2. Chou’s Gauß curvature estimate
15.3.3. Estimate on the radii of curvature
15.3.4. Higher regularity and convergence to a point
§15.4. Differential Harnack estimates
§15.5. Firey’s conjecture
§15.6. Variational structure and entropy formulae
15.6.1. Gradient flow
15.6.2. The Firey entropy
15.6.3. The Gaußian entropy
15.6.4. The general Gaußian entropies
§15.7. Notes and commentary
§15.8. Exercises
Chapter 16. The Affine Normal Flow
§16.1. Affine invariance
§16.2. Affine-renormalized solutions
16.2.1. Gauß curvature bound
16.2.2. Gauß curvature lower bound
16.2.3. Radius of curvature bound
16.2.4. Higher regularity
§16.3. Convergence and the limit flow
§16.4. Self-similarly shrinking solutions are ellipsoids
§16.5. Convergence without affine corrections
§16.6. Notes and commentary
§16.7. Exercises
Chapter 17. Flows by Superaffine Powers of the Gauß Curvature
§17.1. Bounds on diameter, speed, and inradius
17.1.1. The Gauß curvature flow
17.1.2. The α-Gauß curvature flow
§17.2. Convergence to a shrinking self-similar solution
§17.3. Shrinking self-similar solutions are round
17.3.1. Preliminary calculations
17.3.2. Powers \frac{1}{n+2} ≤ α ≤ 1/2
17.3.3. Powers α > 1/2
§17.4. Notes and commentary
§17.5. Exercises
Chapter 18. Fully Nonlinear Curvature Flows
§18.1. Introduction
§18.2. Symmetric functions and their differentiability properties
18.2.1. Functions of curvature
18.2.2. Homogeneity
18.2.3. Concavity
18.2.4. Inverse-concavity
§18.3. Examples
§18.4. Short-time existence
§18.5. The avoidance principle
§18.6. Differential Harnack estimates
§18.7. Entropy estimates
§18.8. Alexandrov reflection
18.8.1. Alexandrov reflection of convex hypersurfaces
18.8.2. Alexandrov reflection of embedded hypersurfaces
§18.9. Notes and commentary
§18.10. Exercises
Chapter 19. Flows of Mean Curvature Type
§19.1. Convex hypersurfaces contract to round points
19.1.1. Preliminaries
19.1.2. Preserving pinching
§19.2. Evolving nonconvex hypersurfaces
19.2.1. Convexity and cylindrical estimates
19.2.2. Noncollapsing
§19.3. Notes and commentary
§19.4. Exercises
Chapter 20. Flows of Inverse-Mean Curvature Type
§20.1. Convex hypersurfaces expand to round infinity
20.1.1. Preliminaries
20.1.2. Geometric estimates
20.1.3. Convergence
§20.2. Notes and commentary
20.2.1. Geometric inequalities
20.2.2. Flows with free boundary
§20.3. Exercises
Bibliography
1-14
15-35
36-55
56-75
76-93
94-116
117-136
137-158
159-177
178-199
200-220
221-242
243-263
264-285
286-306
307-327
328-349
350-371
372-390
391-411
412-431
432-453
454-474
475-496
497-518
519-539
Index
توضیحاتی در مورد کتاب به زبان اصلی :
Extrinsic geometric flows are characterized by a submanifold evolving in an ambient space with velocity determined by its extrinsic curvature. The goal of this book is to give an extensive introduction to a few of the most prominent extrinsic flows, namely, the curve shortening flow, the mean curvature flow, the Gauß curvature flow, the inverse-mean curvature flow, and fully nonlinear flows of mean curvature and inverse-mean curvature type. The authors highlight techniques and behaviors that frequently arise in the study of these (and other) flows. To illustrate the broad applicability of the techniques developed, they also consider general classes of fully nonlinear curvature flows. The book is written at the level of a graduate student who has had a basic course in differential geometry and has some familiarity with partial differential equations. It is intended also to be useful as a reference for specialists. In general, the authors provide detailed proofs, although for some more specialized results they may only present the main ideas; in such cases, they provide references for complete proofs. A brief survey of additional topics, with extensive references, can be found in the notes and commentary at the end of each chapter.