作者thank1984 (thankakimo)
看板Grad-ProbAsk
標題[理工] 離散-Countable
時間Thu Mar 19 16:09:53 2009
題目: If A and B are two countable sets,show that A*B is also countable.
問題: 請問各位大大這題要如何解答呢 ?? 煩請指導 感謝
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1F：推 PALAPO:我只想到 N*N -> N 這樣証 不知道對不對 03/19 16:11
2F：→ SansWord:A -> N, B -> N 03/19 17:39
3F：→ SansWord:A*B -> N -> N -> N 03/19 17:40
4F：→ SansWord:so, A*B is countable 03/19 17:40
5F：→ SansWord:第二行打錯...更正:A*B -> N*N -> N 03/19 17:40
6F：→ thank1984:瞭解了 感謝S大和P大解答 03/19 21:10