International Journal of Mathematics and Mathematical Sciences
Volume 13 (1990), Issue 4, Pages 813-816
doi:10.1155/S0161171290001132
On a theorem of H. Hopf
Takis Sakkalis
Department of Mathematical Sciences, New Mexico State University, Las Cruces 88003, New Mexico, USA
Abstract
A simple proof of a theorem of H. Hopf [1], via Morse theory, is given.