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Question

Math 6510 • Differentiable Manifolds

Fall 2003 • Question 10

Let \(\Sigma \) be an oriented genus 2 surface smoothly embedded in \(\mathbb {R}^3\).

  1. Describe the Gauss map \(g:\Sigma \to S^2\) and define the Gaussian curvature at a point of \(\Sigma \) in terms of \(g\).
  2. State the Gauss-Bonnet theorem for this situation.
  3. Prove that \(\Sigma \) has (many) saddle points, i.e. points of negative curvature.

Raw LaTeX

Let \(\Sigma\) be an oriented genus 2 surface smoothly embedded in \(\mathbb{R}^3\).
\begin{enumerate}
\item Describe the Gauss map \(g:\Sigma\to S^2\) and define the Gaussian curvature at a
point of \(\Sigma\) in terms of \(g\).
\item State the Gauss-Bonnet theorem for this situation.
\item Prove that \(\Sigma\) has (many) saddle points, i.e. points of negative curvature.
\end{enumerate}