11 papers · 1 filter
Analyticity, rank one perturbations and the invariance of the left spectrum
Sameer Chavan, Soumitra Ghara, Paramita Pramanick
We address the question of the analyticity of a rank one perturbation of an analytic operator. If is the bounded operator of multiplication by on a functional Hi…
Weakly concave operators
Sameer Chavan, Jan Stochel
We study a class of left-invertible operators which we call weakly concave operators. It includes the class of concave operators and some subclasses of expansive strict -isometr…
Dirichlet polynomials and a moment problem
Sameer Chavan, Chaman Kumar Sahu
Consider a linear functional defined on the space of Dirichlet polynomials with real coefficients and the set of non-negative elements in $\ma…
The Cauchy dual subnormality problem via de Branges-Rovnyak spaces
Sameer Chavan, Soumitra Ghara, Md Ramiz Reza
The Cauchy dual subnormality problem (for short, CDSP) asks whether the Cauchy dual of a -isometry is subnormal. In this paper, we address this problem for cyclic -isometries…
The Cauchy dual subnormality problem for cyclic -isometries
Akash Anand, Sameer Chavan, Zenon Jan Jabłoński +1
The Cauchy dual subnormality problem asks whether the Cauchy dual operator of a -isometry is subnormal. Recently this problem has been solved in the negative. Here we show that…
Dirichlet-type spaces on the unit ball and joint 2-isometries
Sameer Chavan, Rajeev Gupta, Md. Ramiz Reza
We obtain a formula that relates the spherical moments of the multiplication tuple on a Dirichlet-type space to a complex moment problem in several variables. This can be seen as t…