1977), pp. 113–146, Academic Press, New York-London, 1979. MichelKervaire(英语:MichelKervaire), Smooth homology spheres and their fundamental groups, Transactions
Siebenmann证明了大于4维的紧拓扑流形上的PL结构(英语:Piecewise linear manifold)数目是有限的。约翰·米尔诺、MichelKervaire(英语:MichelKervaire)以及Morris Hirsch证明了一个紧PL流形上的光滑结构数目是有限的且与同样维数球面上光滑结构的数目相等(参见Asselmeyer-Maluga
74 (2): 575–590. JSTOR 1970299. MR 0133127. doi:10.2307/1970299. Kervaire, Michel A.; Milnor, John W. Groups of homotopy spheres: I. Annals of Mathematics