The only Wiedersehen surfaces are the standard round spheres. The conjecture was proven by combining the Berger-Kazdan comparison theorem with A. Weinstein's results for even and C. T. Yang's for odd. Green (1963) obtained the first proof of the Blaschke's conjecture in the two-dimensional case.
See alsoWiedersehen Surface
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ReferencesChavel, I. Riemannian Geometry: A Modern Introduction. New York: Cambridge University Press, 1994.Green, L. W., "Auf Wiedersehensflächen." Ann. Math. 78, 289-299, 1963.
Referenced on Wolfram|AlphaBlaschke Conjecture
Cite this as:
Weisstein, Eric W. "Blaschke Conjecture." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/BlaschkeConjecture.html