2009年1月15日

[Notes] Differential Geometry of Curves and Sufaces



Textbook: Differential Geometry of Curves and Surfaces, Do Carmo
 
有人說幾何學是數學家的試金石,如果你不排斥,那麼你就可以當數學家。
大學幾何和高中幾何是完全不同的範疇,是高斯之所以被稱作數學王子的學問。
  • Chp 1 ~ 3.3 + 4.2
    Curve Theory
        Arc length parameter and arbitrary parameter
        Serret-Frenet Formula
        Fundamental Theorem of Curve Local Theory
        Turning Tangents Theorem
        Osculating Plane
        Center of Curvature
        Huygens Pendulum and Envelopes
        2-D Continuous Rigid Motion

    Surface Theory
        Regular Surface and Local Coordinates
        Regular Value and Singularity
        Change of Surface Coordinates
        Differentiability of Surface
        Surface of Revolution
        Parameterized Surface
        Differential
        Tangent Plane
        Inverse Function Theorem

    First Fundamental Form
        Isometric and Conformal Mapping
        Orientation and Normal Vector Field

    Second Fundamental Form
        Normal Curvature
        Gauss Curvature
        Mean Curvature
        Principal Direction
        Umbilical points
        Line of Curvature and Asymptotic Direction
        Dupin Indicatrix
  • Chp 3.4, 3.5, 4.3~4.4

    Surface Theory
        Developable Surface
        Local Property of Tangent Plane
        Conjugate Direction and Dupin Indicatrix
        Vector Field, Trajectory and Integral Curve
        Special coordinate curves

        Ruled Surface
        Doubly Ruling
        Geometric Deduction of Line of striction and Second Defining Property
        Distributed Parameter and Curvature of Ruling
        3-D Continuous Rigid Motion

        Theorema Egregium
        Compatibility Equations and Christoffel Symbols
        Fundamental Theorem of Surface Local Theory (Bonnet Theorem)

        Covariant Derivatives and Parallel Transport
        Geodesic and Geodesic Curvature
        Lioville Formula
        Geodesic Form of Surface of Revolution
        Clairant Relation
  • Chp 4.5

    Surface Theory

        Gauss-Bonnet Theorem
        The Turning Tangent Theorem
        Jacobi Theorem
        Poincare Theorem

2009年1月8日

幾何本日大定理

剛剛在系K念幾何 唸到 Gauss-Bonnet 定理的一個應用:

引理:
  曲面 S 上高斯曲率恆不正,上面有一點 p 高斯曲率為負。
  看 S 上過點 p 的 simple smooth closed測地線 Γ,
  令 Γ圍出一個 region R,則 R 不可以是 simple region。