天气预报 > 其他 > 数学空集是什么
数学空集是什么
更新时间: 2020-09-23 00:00:00  

空集是指不含任何元素的集合。空集是任何集合的子集,是任何非空集合的真子集。空集不是无。它是内部没有元素的集合。可以将集合想象成一个装有元素的袋子,而空集的袋子是空的,但袋子本身确实是存在的。

关键词: 数学 什么

数学空集是什么相关经验

天气预报

最新推荐

页面:/news/view-285898/ | 耗时:0.6780 s | 内存:2.11 MB | 查询:4 | 缓存读取:3 写入:0 | 加载文件:25
select * from tbl_Articles WHERE ArticleID=285898 LIMIT 0,1
select * from tbl_Articles_data WHERE ArticleID=285898 LIMIT 0,1
select * from tbl_Articles_sphinx where id=285898 LIMIT 0,1
SELECT ArticleID,Title FROM tbl_Articles WHERE ArticleID IN(1092976,1110730,1069992,1099819,1117896,1126022,1100623,1071265,1118495,1074276,1073407,1083113,1058085,1068532,1103121,1065589,1078717,1097889,1070848,1086458,1116627,1045843,1083249,1067487,1066362,1120801,1073100,1049170,1042765,1125385) ORDER BY field (ArticleID,1092976,1110730,1069992,1099819,1117896,1126022,1100623,1071265,1118495,1074276,1073407,1083113,1058085,1068532,1103121,1065589,1078717,1097889,1070848,1086458,1116627,1045843,1083249,1067487,1066362,1120801,1073100,1049170,1042765,1125385)