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发帖数: 164 | 1 Every finite dimensional subspace Y
of a normed space X is complete. In particular, every finite dimensional
normed space is complete.
求证明！ | E*****T
发帖数: 1193 | 2 设e_1,...e_n为一组正交基，子空间的一个Cauchy sequence{A_i}为\sum a^i_j e_j,
从而对每一个j,{a^i_j}为Cauchy sequence, 故有极限$a_j$.容易验证A_i趋近于\sum
a_j e_j. |
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