精華區beta Math 關於我們 聯絡資訊
1. Does there exist an infinite σ-algebra that has only countably many element? 2. Let E be a measurable subset of [0,1]. Let A={ x^1/2 | x is in E }. Is A a measurable subset of [0,1]? 先感謝各位解答了 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.114.123.98