Surjit Kumar

activity

20172026

collaborators

8 papers

math.FA2026

Circular operators and their strong circularity

Soumitra Ghara, Surjit Kumar, Shailesh Trivedi

Circular operators have been studied extensively since the work of R. Gellar, who conjectured that every circular operator on a complex separable Hilbert space is strongly circular…

math.FA2025

Weakly $U (d)$ -homogeneous commuting tuple of bounded operators

Soumitra Ghara, Surjit Kumar, Shailesh Trivedi

We introduce and study the weakly $U (d)$ -homogeneous commuting tuple of operators. We provide a sufficient condition under which a weakly $U (d)$ -homogeneous tuple…

math.FA2024

A short note on similarity of operator-valued multishifts

Soumitra Ghara, Surjit Kumar, Shailesh Trivedi

A complete characterization of the similarity between two operator-valued multishifts with invertible operator weights is obtained purely in terms of operator weights. This general…

math.FA2022

Commuting Tuple of Multiplication Operators Homogeneous under the Unitary Group

Soumitra Ghara, Surjit Kumar, Gadadhar Misra +1

Let $U (d)$ be the group of $d \times d$ unitary matrices. We find conditions to ensure that a $U (d)$ -homogeneous $d$ -tuple $T$ is unitarily equivalent…

math.FA2020

$K$ -homogeneous tuple of operators on bounded symmetric domains

Soumitra Ghara, Surjit Kumar, Paramita Pramanick

Let $Ω$ be an irreducible bounded symmetric domain of rank $r$ in $C^{d} .$ Let $K$ be the maximal compact subgroup of the identity component $G$ of the biholomorphic…

math.FA2019

Unitary equivalence of operator-valued multishifts

Rajeev Gupta, Surjit Kumar, Shailesh Trivedi

We systematically study various aspects of operator-valued multishifts. Beginning with basic properties, we show that the class of multishifts on the directed Cartesian product of…

math.FA2018

Von Neumann's inequality for commuting operator-valued multishifts

Rajeev Gupta, Surjit Kumar, Shailesh Trivedi

Recently, Hartz proved that every commuting contractive classical multishift with non-zero weights satisfies the matrix-version of von Neumann's inequality. We show that this resul…

math.FA2017

On sum of two subnormal kernels

Soumitra Ghara, Surjit Kumar

We show, by means of a class of examples, that if $K_{1}$ and $K_{2}$ are two positive definite kernels on the unit disc such that the multiplication by the coordinate function on the…

Circular operators and their strong circularity

Weakly U(d)-homogeneous commuting tuple of bounded operators

A short note on similarity of operator-valued multishifts

Commuting Tuple of Multiplication Operators Homogeneous under the Unitary Group

K-homogeneous tuple of operators on bounded symmetric domains

Unitary equivalence of operator-valued multishifts

Von Neumann's inequality for commuting operator-valued multishifts

On sum of two subnormal kernels

Weakly $U (d)$ -homogeneous commuting tuple of bounded operators

$K$ -homogeneous tuple of operators on bounded symmetric domains