The generalization of the Schönflies theorem to dimensions. A smoothly embedded -hypersphere in an -hypersphere separates the -hypersphere into two components, each homeomorphic to -balls. It can be proved using Morse theory.
Mazur's Theorem
See also
Ball, Hypersphere, Morse TheoryExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Mazur's Theorem." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/MazursTheorem.html