Re: [高微] 拓撲

看板Math作者mack (腦海裡依然記得妳)時間13年前 (2012/11/24 18:38)推噓6(6推 0噓 0→)

留言6則, 4人參與討論串2/3 (看更多)

※ 引述《y15973 (B.H.Justin)》之銘言： : 一題 : n : 若A，B為R 且A、B皆closed : 令A+B={ a+b | a屬於A，b屬於B } : 試舉一例A+B亦為closed A = {(0,0,0,...,0)} is closed B = {(0,0,0,...,1)} is closed A+B = {(0,0,0,...,1)} is closed -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 125.224.32.113

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herstein

11/24 19:39, , 1^F

11/24 19:39, 1^F

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zako1113

11/24 19:44, , 2^F

11/24 19:44, 2^F

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znmkhxrw

11/24 19:58, , 3^F

11/24 19:58, 3^F