摘要: It is customary to call the function function defined on $U$ by $\nabla_{\frac{\partial}{\partial x_i}}\frac{\partial}{\partial x_j}=\sum\limits_k\Gam 阅读全文
posted @ 2021-04-01 17:14 Minimal_Cone 阅读(130) 评论(0) 推荐(0) 编辑