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[数学] sub math problems [复制链接]

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发表于 2009-9-1 22:42:45 |只看该作者 |倒序浏览
I have two sub math problems.

58 If f(z) is an analytic function that maps the entire finite complex plane into the real axis, then the imaginary axis must be mapped ontoanswer: "a point"does someone know why?

64 Let S be a compact topological space, let T be a topological space, and let f be a function from S onto T. Of the following conditions on f, which is the weakest condition sufficient to ensure the compactness of T?(A) f is homeomorphism; (B) f is continuous and 1-1; (C) f is continuous; (D) f is 1-1; (E) f is boundedanswer: (C)why f is 1-1 is not the weakest sufficient condition? and does f bounded imply T is compact?
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发表于 2009-11-1 19:52:51 |只看该作者
58 by C-R equation, it is trivial;

64 also trivial; 1-1 just means they have the same cardinal number, say there is a 1-1 map between [0,1] and (0,1) , but [0,1] is compact, (0,1) is not.
In 64. bounded is meaningless, since T is only a TOP space, not a metric space
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RE: sub math problems [修改]

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sub math problems
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