[離散] Hamilton Paths and Cycles 一處證明

看板Math作者 (眾人皆濁我更濁)時間12年前 (2014/01/09 07:40), 編輯推噓1(102)
留言3則, 2人參與, 最新討論串1/1
theorem: Let G = (V,E) be a loop-free graph with |V| = n >= 2. If deg(x)+deg(y) >= n-1 for all x,y ε(屬於) V, x≠y, then G has a Hamilton path. proof:First we prove that G is connected. If not, let C1,C2 be two components of G and let x,yεV with x a vertex in C1 and y a vertex in C2. Let Ci have ni vertices,i = 1,2.Then deg(x) <= n1-1,deg(y) <= n2-1, and deg(x)+deg(y) <= (n1+n2)-2 <= n-2, contradicting the condition given in the theorem. Consequently, G is connected. 這只是前半段的證明,先證明G是connected,但 何以從命題以及前述得到黃色的那段Then? 資質駑鈍的我想了好久卻看不出端倪... 希望好心人能幫我解惑 在此先獻上十二萬分的感謝! (DISCRETE and COMBINATORIAL MATHEMATICS by Ralph P. Grimaldi 5th Ed p.560) -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.44.194.107 ※ 編輯: gentlefaith 來自: 114.44.194.107 (01/09 07:45)

01/09 09:13, , 1F
如果是simple and loop free,n1個點最多則其中不管
01/09 09:13, 1F

01/09 09:14, , 2F
哪一個點,他的deg 最多只能是 n1-1。
01/09 09:14, 2F

01/09 12:47, , 3F
喔喔,恍然大悟,感激不盡! XD
01/09 12:47, 3F
文章代碼(AID): #1IpU7OKr (Math)