[理工] [離散]97台大電機
目如下:
第一題
Let V be the set of vertices of a digraph D, and for u,v屬於 V, defined
(u,v)屬於 R if u=v or there exists a path from u to v.Is R equivalence
relation?
答案是NO
為什麼??
我覺得三個條件都符合耶~~
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第二題
Let R be the relation defined on NxN (N為自然數) as follows:((m,n),(p,q))屬於R
iff m≡p mod 3 or n≡q mod 5. Which of the following is false?
(1)R is equivalence relation.
(2)R is reflexive.
(3)R is symmetric.
(4)R is not transitive.
(5)None of the above.
答案是(1)
可是我覺得R應該不符合symmetric...
所以應該是(1)(3)
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以上
有勞高手解答
鋼溫!!
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