Linear Operators: General theory |
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Page 424
Since each projection is a continuous map , each o the sets A ( x , y ) and B ( « , x
) is closed . Hence tK = n x , ve ¥ A ( x , y ) nnaeyrex 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 ( « , x
) is closed . Hence tK = n x , ve ¥ A ( x , y ) nnaeyrex B ( a , x ) is also closed .
Q.E.D. 2 THEOREM . ( Alaoglu ) The closed unit sphere in the conjugate space X
...
Page 429
( Krein - Šmulian ) A convex set in X * is X - closed if and only if its intersection
with every positive multiple of the closed unit sphere of X * is X - closed . Proof .
This follows from the preceding theorem and Corollary 2.14 . Q.E.D.
COROLLARY .
( Krein - Šmulian ) A convex set in X * is X - closed if and only if its intersection
with every positive multiple of the closed unit sphere of X * is X - closed . Proof .
This follows from the preceding theorem and Corollary 2.14 . Q.E.D.
COROLLARY .
Page 488
It follows from the definition of U * that every element in its range satisfies the
stated condition . Q.E.D. 3 LEMMA . If the adjoint of an operator U in B ( X , Y ) is
one - to - one and has a closed range , then UX = Y. Ux = PROOF . Let 0 #ye Y
and ...
It follows from the definition of U * that every element in its range satisfies the
stated condition . Q.E.D. 3 LEMMA . If the adjoint of an operator U in B ( X , Y ) is
one - to - one and has a closed range , then UX = Y. Ux = PROOF . Let 0 #ye Y
and ...
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Contents
Preliminary Concepts | 1 |
B Topological Preliminaries | 10 |
Algebraic Preliminaries | 34 |
Copyright | |
80 other sections not shown
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