Chattopadhyay, Arup Das, Soma Pradhan, Chandan
Published in
Integral Equations and Operator Theory
In this article, we characterize nearly invariant subspaces of finite defect for the backward shift operator acting on the vector-valued Hardy space which is a vectorial generalization of a result of Chalendar–Gallardo–Partington. Using this characterization of nearly invariant subspace under the backward shift we completely describe the almost inv...
Li, Yongning Sang, Yuanqi Ding, Xuanhao
Published in
Banach Journal of Mathematical Analysis
Dual truncated Toeplitz operators on the orthogonal complement of the model space Ku2(=H2⊖uH2)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_u^2(=H^2 \ominus uH^2)$$...
Peebles, Thomas Stessin, Michael
Published in
Advances in Operator Theory
We prove that if for a pair of n×n\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n\times n$$\end{document} matrices A and B, with A being normal, the projective joint ...
Pamula, Santhosh Kumar
Published in
Banach Journal of Mathematical Analysis
Let H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {H}$$\end{document} be a right quaternionic Hilbert space and let T be a bounded quaternionic normal opera...
Chō, Muneo Beiba, El Moctar Ould Mahmoud, Sid Ahmed Ould Ahmed
Published in
Annals of Functional Analysis
Our aim in this paper is to consider a generalization of the concept of n-quasi-m-isometric operators of a single operator done in Mahmoud Sid Ahmed et al. (Results Math 73:511–531, 2018) and Mechri and Mahmoud Sid Ahmed (Oper Matrices 14(1): 145–157, 2020) to the multi-dimensional operators. We discuss the most interesting results concerning these...
Enomoto, Masatoshi Watatani, Yasuo
Published in
Advances in Operator Theory
We study two subspace systems in a separable infinite-dimensional Hilbert space up to (bounded) isomorphism. One of the main result of this paper is the following: Isomorphism classes of two subspace systems given by graphs of bounded operators are determined by unitarily equivalent classes of the operator ranges and the nullity of the original bou...
Wu, Chang Hui Yu, Tao
Published in
Acta Mathematica Sinica, English Series
Let H2(ⅅ2) be the Hardy space over the bidisk ⅅ2, and let Mψ,ϕ = [(ψ(z) − ϕ(w))2] be the submodule generated by (ψ(z) − ϕ(w))2, where ψ(z) and ϕ(w) are nonconstant inner functions. The related quotient module is denoted by Nψ,ϕ = H2(ⅅ2) ⊖ Mψ,ϕ. In this paper, we give a complete characterization for the essential normality of Nψ,ϕ. In particular, if...
Solel, Baruch
Published in
Integral Equations and Operator Theory
The techniques developed by Popescu, Muhly-Solel and Good for the study of algebras generated by weighted shifts are applied to generalize results of Sarkar and of Bhattacharjee-Eschmeier-Keshari-Sarkar concerning dilations and invariant subspaces for commuting tuples of operators. In that paper the authors prove Beurling-Lax-Halmos type results fo...
Timotin, Dan
Published in
Concrete Operators
Using the tools of Sz.-Nagy–Foias theory of contractions, we describe in detail the invariant subspaces of the operator S ⊕ S*, where S is the unilateral shift on a Hilbert space. This answers a question of Câmara and Ross.
Li, Yufei Yang, Yixin Lu, Yufeng
Published in
Complex Analysis and Operator Theory
Let T be a contraction on the Hilbert space H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathscr {H}$$\end{document} and S a minimal isometric dilation of T. In th...