The Poincaré conjecture has been in the news lately. Russian mathematician Grigori Perelman submitted a proof 3 years ago claiming that he had proved the famous conjecture. In August, he won a ...

https://doi.org/10.4169/amer.math.monthly.119.05.373 • https://www.jstor.org/stable/10.4169/amer.math.monthly.119.05.373 Copy URL Abstract We consider positive ...