Book contents
- Frontmatter
- Dedication
- Contents
- Preface
- Introduction
- 1 Geometry of Surfaces in R3
- 2 Vector Fields
- 3 Sub-Riemannian Structures
- 4 Pontryagin Extremals: Characterization and Local Minimality
- 5 First Integrals and Integrable Systems
- 6 Chronological Calculus
- 7 Lie Groups and Left-Invariant Sub-Riemannian Structures
- 8 Endpoint Map and Exponential Map
- 9 2D Almost-Riemannian Structures
- 10 Nonholonomic Tangent Space
- 11 Regularity of the Sub-Riemannian Distance
- 12 Abnormal Extremals and Second Variation
- 13 Some Model Spaces
- 14 Curves in the Lagrange Grassmannian
- 15 Jacobi Curves
- 16 Riemannian Curvature
- 17 Curvature in 3D Contact Sub-Riemannian Geometry
- 18 Integrability of the Sub-Riemannian Geodesic Flow on 3D Lie Groups
- 19 Asymptotic Expansion of the 3D Contact Exponential Map
- 20 Volumes in Sub-Riemannian Geometry
- 21 The Sub-Riemannian Heat Equation
- Appendix Geometry of Parametrized Curves in Lagrangian Grassmannians Igor Zelenko
- References
- Index
9 - 2D Almost-Riemannian Structures
Published online by Cambridge University Press: 28 October 2019
Book contents
- Frontmatter
- Dedication
- Contents
- Preface
- Introduction
- 1 Geometry of Surfaces in R3
- 2 Vector Fields
- 3 Sub-Riemannian Structures
- 4 Pontryagin Extremals: Characterization and Local Minimality
- 5 First Integrals and Integrable Systems
- 6 Chronological Calculus
- 7 Lie Groups and Left-Invariant Sub-Riemannian Structures
- 8 Endpoint Map and Exponential Map
- 9 2D Almost-Riemannian Structures
- 10 Nonholonomic Tangent Space
- 11 Regularity of the Sub-Riemannian Distance
- 12 Abnormal Extremals and Second Variation
- 13 Some Model Spaces
- 14 Curves in the Lagrange Grassmannian
- 15 Jacobi Curves
- 16 Riemannian Curvature
- 17 Curvature in 3D Contact Sub-Riemannian Geometry
- 18 Integrability of the Sub-Riemannian Geodesic Flow on 3D Lie Groups
- 19 Asymptotic Expansion of the 3D Contact Exponential Map
- 20 Volumes in Sub-Riemannian Geometry
- 21 The Sub-Riemannian Heat Equation
- Appendix Geometry of Parametrized Curves in Lagrangian Grassmannians Igor Zelenko
- References
- Index
Summary
Almost-Riemannian structures form prototypes forrank-varying sub-Riemannian structures. In thischapter we study the two-dimensional case, which isvery simple since it is Riemannian almost everywherebut even so presents some interesting phenomena suchas the presence of sets of finite diameter butinfinite area. Also, the Gauss–Bonnet theorem has asurprising form in this context.
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- A Comprehensive Introduction to Sub-Riemannian Geometry , pp. 295 - 330Publisher: Cambridge University PressPrint publication year: 2019