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In this paper, we describe necessary and sufficient conditions for a binormal or complex symmetric operator to have the other property. Along the way, we find connections to the Duggal and Aluthge transforms, and give further properties of…

Functional Analysis · Mathematics 2017-05-16 Caleb Holleman , Thaddeus McClatchey , Derek Thompson

We prove that an injective, not necessarily bounded weighted bilateral shift operator on $\ell^2(\mathbb{Z})$ is similar to a normal operator if and only if it is similar to a scalar multiple of the simple (i.e. unweighted) bilateral shift…

Functional Analysis · Mathematics 2015-06-08 György Pál Gehér

In this note, we introduce the notion of $r$-homoclinic points. We show that an operator on a Banach space is hyperbolic if and only if it is shadowing and has no nonzero $r$-homoclinic points. We also solve invariant subspace problem (ISP…

Dynamical Systems · Mathematics 2022-09-19 Linh T. T. Tran

Let $A = U |A|$ be the polar decomposition of $A$. The Aluthge transform of the operator $A$, denoted by $\tilde{A}$, is defined as $\tilde{A} =|A|^{\frac{1}{2}} U |A|^{\frac{1}{2}}$. In this paper, first we generalize the definition of…

Functional Analysis · Mathematics 2017-10-16 Mojtaba Bakherad , Khalid Shebrawi

Hyponormal operators are known to be among the most difficult operators to analyze. In this work, we focus on two finite types of hyponormal operators. The first type becomes analytic shifts, while the second type admits analytic models. A…

Functional Analysis · Mathematics 2026-02-27 Sneha B , Neeru Bala , Jaydeb Sarkar

Aluthge transform is a well-known mapping defined on bounded linear operators. Especially, the convergence property of its iteration has been studied by many authors. In this paper, we discuss the problem for the induced Aluthge transforms…

Functional Analysis · Mathematics 2024-09-06 Hiroyuki Osaka , Takeaki Yamazaki

The main purpose of this paper is to study the generalized Hilbert operator {equation*} \mathcal{H}_g(f)(z)=\int_0^1f(t)g'(tz)\,dt {equation*} acting on the weighted Bergman space $A^p_\om$, where the weight function $\om$ belongs to the…

Complex Variables · Mathematics 2013-03-12 José Ángel Peláez , Jouni Rättyä

For commuting linear operators $P_0,P_1,..., P_\ell$ we describe a range of conditions which are weaker than invertibility. When any of these conditions hold we may study the composition $P=P_0P_1... P_\ell$ in terms of the component…

Operator Algebras · Mathematics 2007-06-19 A. Rod Gover , Josef Silhan

We prove an extrapolation result for general operators under some weak assumptions on the boundedness of the operator. In particular, we show that if the operator is weakly bounded on some L^{p_{0}}(w), for all "flat" weights, w in…

Classical Analysis and ODEs · Mathematics 2012-04-19 Nicholas Boros , Nikolaos Pattakos , Alexander Volberg

This paper introduces and investigates the class of \textit{$k$-quasi $n$-power posinormal operators} in Hilbert spaces, generalizing both posinormal and $n$-power posinormal operators. We establish fundamental properties including matrix…

Functional Analysis · Mathematics 2025-09-18 Sophiya S Dharan , T. Prasad , M. H. M. Rashid

Defining conditions for irreducible tensor operators associated with the unitary irreducible corepresentations of compact quantum group algebras are deduced within the framework of the abstract carrier space formalism. It is shown that…

q-alg · Mathematics 2009-10-30 J. F. Cornwell

We obtain in this short article the non-asymptotic exact estimations for the norm of (generalized) weighted Hardy-Littlewood average integral operator in the so-called Bilateral Grand Lebesgue Spaces. We also give examples to show the…

Functional Analysis · Mathematics 2013-09-03 E. Ostrovsky , L. Sirota

In the paper two-weighted norm estimates with general weights for Hardy-type transforms, maximal functions, potentials and Calder\'on-Zygmund singular integrals in variable exponent Lebesgue spaces defined on quasimetric measure spaces $(X,…

Functional Analysis · Mathematics 2010-07-09 Vakhtang Kokilashvili , Alexander Meskhi And Muhammad Sarwar

Let $\mathcal{M}\subseteq\mathcal{B}\left( \mathcal{H}\right) $ be a countable decomposable properly infinite von Neumann algebra with a faithful normal semifinite tracial weight $\tau$ where $\mathcal{B}\left( \mathcal{H}\right) $ is the…

Operator Algebras · Mathematics 2021-11-08 Xiongfeng Zhan , Yifei Ruan , Henanbei Huang , Qihui Li

We prove a general weak existence theorem for wave operators for hybrid normed ideal perturbations. We then use this result to prove the invariance of Lebesgue absolutely continuous parts of n-tuples of commuting hermitian operators under…

Functional Analysis · Mathematics 2019-04-04 Dan-Virgil Voiculescu

In this note basic properties of unbounded weighted conditional expectation operators are investigated. A description of polar decomposition and quasinormality in this context are provided. Also, we study hyperexpan- sive weighted…

Functional Analysis · Mathematics 2015-02-03 Yousef Estaremi

In this paper, we provide a generalized version of the Voiculescu theorem for normal operators by showing that, in a von Neumann algebra with separable pre-dual and a faithful normal semifinite tracial weight $\tau$, a normal operator is an…

Operator Algebras · Mathematics 2017-06-30 Qihui Li , Junhao Shen , Rui Shi

In this paper we define $\lambda$-hyponormal operators on an infinite dimensional Hilbert space $\mathcal{H}$ and find a class of $\lambda$-hyponormal operators that can not be hypercyclic. Also, we study closedness of range and…

Functional Analysis · Mathematics 2025-08-07 Y. Estaremi , M. S. Al Ghafri , and S. Shamsigamchi

We consider operators acting on a Hilbert space that can be written as the sum of a shift and a diagonal operator and determine when the operator is hyponormal. The condition is presented in terms of the norm of an explicit block Jacobi…

Classical Analysis and ODEs · Mathematics 2021-08-11 Trieu Le , Brian Simanek

We establish a set of relations between several quite diverse types of weighted inequalities involving various integral operators and fairly general quasinorm-like functionals which we call sub-monotone. The main result enables one to solve…

Classical Analysis and ODEs · Mathematics 2025-03-13 Amiran Gogatishvili , Luboš Pick