闭合闭包性质闭包特性包含一个集及其所有极限点的闭合集
The closed closure property: The closure property consists of a set and a closed set of all its limit points
以上为机器翻译结果，长、整句建议使用 人工翻译 。
应用推荐
模块上移
模块下移
不移动