Results 51 to 60 of about 92 (86)

?-Hyponormal operators

Integral Equations and Operator Theory, 2000
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Aluthge, Ariyadasa, Wang, Derming
openaire   +2 more sources

Hyponormal Composition Operators

Bulletin of the London Mathematical Society, 1986
Let (X,\(\Sigma\),m) be a complete \(\sigma\)-finite measure space, and let T be a \(\Sigma\)-measurable mapping in X such that \(m\circ T^{-1}\) is absolutely continuous with respect to m. The corresponding weighted composition operator W on \(L^ 2(X,\Sigma,m)\) generated by the weight function \(\phi\) is defined by \(Wf:=\phi f\circ T\).
openaire   +2 more sources

On spectra ofp-hyponormal operators

Integral Equations and Operator Theory, 1995
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Chō, M., Itoh, M.
openaire   +1 more source

Operations with Hyponormal Operators

1989
It is the aim of the present chapter to collect some of the operations which preserve the class of hyponormal operators. We have already seen in Example II.2.1 that the square of a hyponormal operator may not be hyponormal. Thus the analytic functional calculus is excluded from these operations.
Mircea Martin, Mihai Putinar
openaire   +1 more source

On hyponormality of Toeplitz operators

Rocky Mountain Journal of Mathematics, 2021
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Sadraoui, Houcine, Garayev, Mubariz, Guediri, Hocine   +2 more
openaire   +2 more sources

ON P-HYPONORMAL COMPOSITION OPERATORS

Universal Journal of Mathematics and Mathematical Sciences, 2020
Summary: In this paper, we introduce P-hyponormal composition operators on \(L^2\)-spaces and study some of their properties. We show that Fuglede-Putnam's (briefly FP) theorem holds for P-hyponormal and P-hyponormal composition operators.
openaire   +2 more sources

Square of ω-hyponormal operators

Integral Equations and Operator Theory, 2001
A bounded linear operator \(T\) on a complex Hilbert space with polar decomposition \(T= U|T|\) is said to be \(w\)-hyponormal if \(||T|^{{1\over 2}} U|T|^{{1\over 2}}|\geq |T|\geq ||T|^{{1\over 2}} U^*|T|^{{1\over 2}}\). It is shown that the square of a \(w\)-hyponormal operator itself is \(w\)-hyponormal. This generalizes a result of Althuge and Wang
Chō, M., Huruya, T.
openaire   +2 more sources

Elementary Properties of Hyponormal Operators and Semi-Hyponormal Operators

1983
The spectral analysis of operators has always been one of the interesting and active topics of Operator Theory. The theory of spectral analysis of self-adjoint operators, unitary and normal operators is now an important part of the many textbooks on Functional Analysis. Since the 1950’s, many mathematicians have considered more general linear operators.
openaire   +1 more source

Quadratic Hyponormality and 2-Hyponormality for Toeplitz Operators

Integral Equations and Operator Theory, 2005
In this note we prove the conjecture given in [11]: Let 0 < α < 1 and let ψ be the conformal map of the unit disk onto the interior of the ellipse with vertices ±(1+α)i and passing through ±(1−α). If \( \varphi = \psi + \lambda \overline \psi \) then Tφ is quadratically hyponormal if and only if Tφ is 2–hyponormal.
Sang Hoon Lee, Woo Young Lee
openaire   +1 more source

The Spectra of Completely Hyponormal Operators

American Journal of Mathematics, 1971
1. A bounded operator T on a Hilbert space e is said to be hyponormal if (1. 1) T*T -TT* ==D_O. For a survey of some of the properties of such operators, see Putnam [6]. ilyponormal and normal operators have certain common properties. In particular, if T has the rectangular representation T = H + iJ, so that (1.
openaire   +2 more sources