送交者: xinlihuaxys 于 2008-12-12, 02:16:01:
回答: that is not true, the cardinal of [0, N] and [0, 2N] are exactly the same. 由 steven 于 2008-12-12, 01:55:47:
加跟贴
标题:
内容: (BBCode使用说明)