Blaschke Conjecture
The only Wiedersehen Manifolds are the standard round spheres. The conjecture hasbeen proven by combining the Berger-Kazdan Comparison Theorem with A. Weinstein's results for 
Even and C. T. Yang's for Odd.
References
Chavel, I. Riemannian Geometry: A Modern Introduction. New York: Cambridge University Press, 1994.
- Mirror Image
- Mirror Plane
- Misère Form
- Mitchell Index
- Miter Surface
- Mittag-Leffler Function
- Mittenpunkt
- Mixed Partial Derivative
- Mixed Strategy
- Mixed Tensor
- Mnemonic
- Mock Theta Function
- Mod
- Mode
- Model Completion
- Mode Locking
- Model Theory
- Modified Bessel Differential Equation
- Modified Bessel Function of the First Kind
- Modified Bessel Function of the Second Kind
- Modified Spherical Bessel Differential Equation
- Modified Spherical Bessel Function
- Modified Struve Function
- Modular Angle
- Modular Equation