Absolute continuity and hyponormal operators.
Putnam, C.R. (1981)
International Journal of Mathematics and Mathematical Sciences
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Putnam, C.R. (1981)
International Journal of Mathematics and Mathematical Sciences
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Muneo Chō, Tadasi Huruya, Kôtarô Tanahashi (2005)
Banach Center Publications
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In this paper, we introduce the angular cutting and the generalized polar symbols of a p-hyponormal operator T in the case where U of the polar decomposition T = U|T| is not unitary and study spectral properties of it.
Marcin Bownik, John Jasper (2015)
Bulletin of the Polish Academy of Sciences. Mathematics
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Given a finite set X⊆ ℝ we characterize the diagonals of self-adjoint operators with spectrum X. Our result extends the Schur-Horn theorem from a finite-dimensional setting to an infinite-dimensional Hilbert space analogous to Kadison's theorem for orthogonal projections (2002) and the second author's result for operators with three-point spectrum (2013).
Bernard Morrel, Paul Muhly (1974)
Studia Mathematica
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Vladimir Rakočević (2000)
Publications de l'Institut Mathématique
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Paul Muhly (1974)
Studia Mathematica
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Mohammed Hichem Mortad (2011)
Colloquium Mathematicae
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We present a new approach to the question of when the commutativity of operator exponentials implies that of the operators. This is proved in the setting of bounded normal operators on a complex Hilbert space. The proofs are based on some results on similarities by Berberian and Embry as well as the celebrated Fuglede theorem.
Coddington, E. A.
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György I. Targonski (1967)
Compositio Mathematica
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Zbigniew Burdak, Wiesław Grygierzec (2020)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica
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The n-tuples of commuting Hilbert space contractions are considered. We give a model of a commuting lifting of one contraction and investigate conditions under which a commuting lifting theorem holds for an n-tuple. A series of such liftings leads to an isometric dilation of the n-tuple. The method is tested on some class of triples motivated by Parrotts example. It provides also a new proof of the fact that a positive definite n-tuple has an isometric dilation.