[離散] 離散(2)
Suppose F is a family of subsets of { 1, 2, ..., n } such that
A does not contains B and B does not contains A for any two
distinct A, B in F.
n
Prove that |F|≦( ). Moreover, prove that if equality holds,
└n/2┘
then F consists of all subsets of { 1, 2, ..., n } of size └n/2┘,
or all subsets of size ┌n/2┐ (these are the same if n is even).
--
我好窮啊，我好缺批幣啊
，你有摳摳ㄋㄟ
可憐可憐我吧，施捨一點吧
請到(P)LAY-->(P)AY-->(0)GIVE-->PttFund-->吧
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.112.218.142
→
61.229.112.108 07/25, , 1F
61.229.112.108 07/25, 1F