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Question

Math 6510 • Differentiable Manifolds

Fall 1999 • Question 1

Let \(f:M\to N\) be a submersion between two smooth manifolds (without boundary).

  1. Show that \(f\) is an open map, i.e., if \(U\subseteq M\) is open, then \(f(U)\subseteq N\) is open.
  2. Show that if \(M\) is closed (i.e. compact without boundary) and \(N\) is connected, then \(f\) is onto.
  3. Show that there is no submersion of a closed manifold to \(\mathbb {R}^n\).

Raw LaTeX

Let \(f:M\to N\) be a submersion between two smooth manifolds (without boundary).
\begin{enumerate}
\item Show that \(f\) is an open map, i.e., if \(U\subseteq M\) is open, then
\(f(U)\subseteq N\) is open.
\item Show that if \(M\) is closed (i.e. compact without boundary) and \(N\) is connected,
then \(f\) is onto.
\item Show that there is no submersion of a closed manifold to \(\mathbb{R}^n\).
\end{enumerate}