Re: [理工] [離散] 97 台大電機

看板Grad-ProbAsk作者 (小魯米)時間14年前 (2011/11/19 23:07), 編輯推噓0(001)
留言1則, 1人參與, 最新討論串2/2 (看更多)
四個element 可以想成 F^n n的order 4個 1-cycle =1 2個 1-cycle + 1個 2-cycle =2 2個 2-cycle =2 1個 1-cycle + 1個 3-cycle =3 1個 4-cycle =4 所以n最小為 12 ※ 引述《askaleroux (aska)》之銘言: : Let X be a set of four elements, and let Bx be the set of all : bijective function from X to itself. Clearly, Bx!= none,since the : identity map Ix from x to itself is in Bx. Let B be the set of positive : integers n such that exist f belongs to Bx ,f^n=Ix. : Let n be the smallest element of N. which of the following statements is true? : n= 1,4,6,12 : n does not exist because N=none : ======================================================================== : 答案是12 : 我想我的問題在於Ix我不知道是什麼碗糕 : 有大大能夠幫忙提點一下這一題解法嗎? -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 59.115.77.154

11/19 23:09, , 1F
補充一下Ix的意思類似 f(a)=a 這樣
11/19 23:09, 1F
文章代碼(AID): #1EnyPBGp (Grad-ProbAsk)
文章代碼(AID): #1EnyPBGp (Grad-ProbAsk)