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If A*A is a compact operator, is A compact?

  1. May 25, 2009 #1
    Hi, if I know that A is continuous and linear and A*A is compact, where A* is the adjungate, how will I show that A has to be compact?
  2. jcsd
  3. May 25, 2009 #2


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    You could try using the http://en.wikipedia.org/wiki/Polar_decomposition" [Broken].
    Last edited by a moderator: May 4, 2017
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