4 papers
On -partial isometries: spectra, weighted shifts, and similarity
Mohamed Amine Aouichaoui, Michał Buchała, Stephan Ramon Garcia
The aim of this paper is to study -partial isometries on Hilbert spaces, a natural extension of partial isometries and -isometries. We establish structural and spectral resul…
Every expansive -concave operator has -isometric dilation
Michał Buchała
The aim of this paper is to obtain -isometric dilation of expansive -concave operator on Hilbert space. The obtained dilation is shown to be minimal. The matrix represent…
m-isometric weighted shifts with operator weights
Michał Buchała
The aim of this paper is to study -isometric weighted shifts with operator weights (both unilateral and bilateral). We obtain a characterization of such shifts by polynomials…
M-isometric Composition Operators On Discrete Spaces
Michał Buchała
In this paper we investigate composition operators on discrete spaces. We establish the classification of underlying graphs of such operators. For one class of such graphs, namely…