Answer

问题及解答

求 $\pi_1(S^n)$

Posted by haifeng on 2015-07-19 13:17:18 last update 2015-07-19 13:17:18 | Edit | Answers (0)

$\pi_1(S^1)=\mathbb{Z}$,

$\pi_1(S^n)=0$, 对于 $n\geqslant 2$.