Remarks Concerning Uniformly Bounded Operators on Hilbert Space
1972 ◽
Vol 15
(2)
◽
pp. 215-217
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Keyword(s):
In [6] B. Sz.-Nagy has proved that every operator on a Hilbert space such that1is similar to a unitary operator.The following problem is an extension of this result: If T and S are two operators such that1.sup {‖Tn‖, ‖Sn‖}<∞ (n = 0, ±1, ±2,…)2.TS = STthen there exists a selfadjoint operator Q such that QTQ-1, QSQ-1 are unitary operators?Also, in [7] B. Sz.-Nagy has proved that every compact operator T such thatsup ‖Tn‖<∞ (n = 1, 2, 3,…)is similar to a contraction.
2010 ◽
Vol 88
(2)
◽
pp. 205-230
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Keyword(s):
1979 ◽
Vol 31
(5)
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pp. 1012-1016
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Keyword(s):
1985 ◽
Vol 37
(4)
◽
pp. 664-681
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Keyword(s):
1968 ◽
Vol 32
◽
pp. 141-153
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2020 ◽
Vol 18
(01)
◽
pp. 1941026
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1977 ◽
Vol 24
(2)
◽
pp. 129-138
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1974 ◽
Vol 26
(1)
◽
pp. 247-250
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1986 ◽
Vol 28
(1)
◽
pp. 25-30
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Keyword(s):