Subnormality versus restrictions
The complete hyperexpansivity analog of the Embry conditions
The Embry conditions are a set of positivity conditions that characterize subnormal operators (on Hilbert spaces) whose theory is closely related to the theory of positive definite functions on the additive semigroup ℕ of non-negative integers. Completely hyperexpansive operators are the negative definite counterpart of subnormal operators. We show that completely hyperexpansive operators are characterized by a set of negativity conditions, which are the natural analog of the Embry conditions for...
The Fuglede-Putnam theorem and Putnam's inequality for quasi-class (A, k) operators.
The Fuglede–Putnam theorem for -quasihyponormal operators.
The Spectra of Hyponormal Integral Operators
The support of the associated measure to the Cowen's tridiagonal matrix.
In this paper we consider a class of three-term recurrence relations, whose associated tridiagonal matrices are subnormal operators. In this cases, there are measures associated to the polynomials given by such relations. We study the support of these measures.
Trace formulae for p-hyponormal operators
The purpose of this paper is to introduce mosaics and principal functions of p-hyponormal operators and give a trace formula. Also we introduce p-nearly normal operators and give trace formulae for them.
Uniformly ergodic A-contractions on Hilbert spaces
We study the concept of uniform (quasi-) A-ergodicity for A-contractions on a Hilbert space, where A is a positive operator. More precisely, we investigate the role of closedness of certain ranges in the uniformly ergodic behavior of A-contractions. We use some known results of M. Lin, M. Mbekhta and J. Zemánek, and S. Grabiner and J. Zemánek, concerning the uniform convergence of the Cesàro means of an operator, to obtain similar versions for A-contractions. Thus, we continue the study of A-ergodic...
Unitary dilation for polar decompositions of p-hyponormal operators
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.
Weighted Frobenius-Perron operators and their spectra
First, some classic properties of a weighted Frobenius-Perron operator on as a predual of weighted Koopman operator on will be investigated using the language of the conditional expectation operator. Also, we determine the spectrum of under certain conditions.
Weyl type theorems for p-hyponormal and M-hyponormal operators
"Generalized Weyl's theorem holds" for an operator when the complement in the spectrum of the B-Weyl spectrum coincides with the isolated points of the spectrum which are eigenvalues; and "generalized a-Weyl's theorem holds" for an operator when the complement in the approximate point spectrum of the semi-B-essential approximate point spectrum coincides with the isolated points of the approximate point spectrum which are eigenvalues. If T or T* is p-hyponormal or M-hyponormal then for every f ∈...
Weyl's and Browder's theorem for an elementary operator
Weyl's Theorem for a Generalized Derivation and an Elementary Operator
Weyl's theorem for algebraically absolute--paranormal operators.
Weyl's theorems and continuity of spectra in the class of p-hyponormal operators
We show that p-hyponormal operators obey Weyl's and a-Weyl's theorem. Also, we show that the spectrum, Weyl spectrum, Browder spectrum and approximate point spectrum are continuous functions in the class of all p-hyponormal operators.
Использование ультрапроизведений в теории операторов. Простое доказательство теоремы Бишопа
Кратный сдвиг с простым спектром
Лекции об операторe сдвига. III.
Лекции об операторе сдвига
Лекции об операторе сдвига. II