sequence Xn屬於(0.1) ,
Xn屬於Q,Xn=Pn/Qn in reduced form
{Xn_k}是{Xn}的子序列
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Suppose that there exist integers n_1<n_2<....
such that |Qn_k|≦ M < ∞ for k屬於N.
Since Xn_k屬於(0.1),it follows that the set
E :={Xn_k=Pn_k/Qn_k:k屬於N}
contains only a finite number of points.
Hence, the limit of any sequence in E must belong to E.
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不懂為什麼包含有限的點和極限一定存於E中 >"<
看wade的3.3Continuity章節的習題有的疑惑
請問有人可以解釋一下嗎?感謝
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