A Survey of Some Results on Subnormal Operators

1985 ◽  
pp. 19-37
Author(s):  
John B. Conway
Keyword(s):  
Subnormal Operators

Subnormal Operators

1989 ◽  
pp. 15-40
Author(s):  
Mircea Martin ◽  
Mihai Putinar
Keyword(s):  
Subnormal Operators

scholarly journals Extensions of the Fuglede-Putnam-type theorems to subnormal operators

1985 ◽  
Vol 31 (2) ◽  
pp. 161-169 ◽  
Author(s):  
Takayuki Furuta
Keyword(s):  
Type Theorem ◽  
Degree Of Approximation ◽  
Subnormal Operators ◽  
Normal Operators

At first we investigate the similarity between the Kleinecke-Shirokov theorem for subnormal operators and the Fuglede-Putnam theorem and also we show an asymptotic version of this similarity. These results generalize results of Ackermans, van Eijndhoven and Martens. Also we show two theorems on degree of approximation on subnormal derivation ranges. These results generalize results of Stampfli on degree of approximation on normal derivation ranges. The purpose of this paper is to show that the Fuglede-Putnam-type theorem on normal operators can certainly be generalized to subnormal operators.

scholarly journals A functional calculus for subnormal operators

1976 ◽  
Vol 82 (2) ◽  
pp. 259-262
Author(s):  
John B. Conway ◽  
Robert F. Olin
Keyword(s):  
Functional Calculus ◽  
Subnormal Operators

scholarly journals A class of pure subnormal operators.

1977 ◽  
Vol 24 (1) ◽  
pp. 115-118
Author(s):  
Robert F. Olin
Keyword(s):  
Subnormal Operators

scholarly journals A characterization of subnormal operators

1984 ◽  
Vol 25 (1) ◽  
pp. 99-101 ◽  
Author(s):  
Alan Lambert
Keyword(s):  
Hilbert Space ◽  
Hilbert Spaces ◽  
Commutative Algebras ◽  
Binomial Expansion ◽  
Subnormal Operators

In this note a characterization of subnormality of operators on Hilbert space is given. The characterization is in terms of a sequence of polynomials in the operator and its adjoint reminiscent of the binomial expansion in commutative algebras. As such no external Hilbert spaces are needed, nor is it necessary to introduce forms dependent on arbitrary sequences of vectors from the Hilbert space.

On Quasisimilarity for Subnormal Operators, II

1982 ◽  
Vol 25 (1) ◽  
pp. 37-40 ◽  
Author(s):  
John B. Conway
Keyword(s):  
Subnormal Operator ◽  
Unilateral Shift ◽  
Closed Algebra ◽  
Subnormal Operators ◽  
Weak Star

AbstractLet S be a subnormal operator and let be the weak-star closed algebra generated by S and 1. An example of an irreducible cyclic subnormal operator S is found such that there is a T in with S and T quasisimilar but not unitarily equivalent. However, if S is the unilateral shift, T ∈ and S and T are quasisimilar, then S ≅ T.

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