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Page 424
Since each projection is a continuous map , each o the sets A ( x , y ) and B ( a , x
) is closed . Hence tK = ngxex A ( x , y ) o nae , rex B ( a , x ) is also closed . Q . E .
D . 2 THEOREM . ( Alaoglu ) The closed unit sphere in the conjugate space X ...
Since each projection is a continuous map , each o the sets A ( x , y ) and B ( a , x
) is closed . Hence tK = ngxex A ( x , y ) o nae , rex B ( a , x ) is also closed . Q . E .
D . 2 THEOREM . ( Alaoglu ) The closed unit sphere in the conjugate space X ...
Page 488
If the adjoint of an operator U ' in B ( X , Y ) is one - to - one and has a closed
range , then UX = Y . PROOF . Let 0 # ye Y and define I = { y * y * e Y * , y * y = 0 }
. Then I ' is Y - closed in Y * . Suppose , for the moment , that U * l ' is X - closed
and ...
If the adjoint of an operator U ' in B ( X , Y ) is one - to - one and has a closed
range , then UX = Y . PROOF . Let 0 # ye Y and define I = { y * y * e Y * , y * y = 0 }
. Then I ' is Y - closed in Y * . Suppose , for the moment , that U * l ' is X - closed
and ...
Page 489
since the range of U * is closed , * = U * y * for some y * e Y * . If z * is the
restriction of y * to 3 , then w * = U * * * . Hence , the range of U * is also closed . It
follows from the previous lemma that U _ X = UX = 3 . Hence , U has a closed
range .
since the range of U * is closed , * = U * y * for some y * e Y * . If z * is the
restriction of y * to 3 , then w * = U * * * . Hence , the range of U * is also closed . It
follows from the previous lemma that U _ X = UX = 3 . Hence , U has a closed
range .
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Contents
Metric Spaces | 19 |
Convergence and Uniform Convergence of Generalized | 26 |
Exercises | 33 |
Copyright | |
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