Kalpesh J. Haria

activity

20112026

collaborators

10 papers

math.FA2026

Regularity of the Sz.-Nagy and Foiaş Factorization of Characteristic Functions and Its Multivariable Analogue

Kalpesh J. Haria, Aashish Kumar Maurya

Given a contraction with an invariant subspace and a row contraction with a joint invariant subspace, a factorization of their characteristic functions was obtained by Sz.-Nagy and…

math.FA2026

$k$ -Regular Factorizations and Joint Invariant Subspaces of Completely Non-Coisometric Row Contractions

Kalpesh J. Haria, Aashish Kumar Maurya

This article investigates $k$ -regular factorizations of characteristic functions associated with completely non-coisometric row contractions. In this setting, a one-to-one correspo…

math.OA2026

$k$ -Regular Factorizations and Invariant Subspaces of Completely Non-Unitary Contractions

Kalpesh J. Haria, Aashish Kumar Maurya

We introduce the notion of $k$ -regular factorizations for contractions into $k$ factors, generalizing the classical notion of regular factorization due to Sz.-Nagy and Foiaş, and d…

math.FA2023

Characteristic Functions and Colligations

Neeru Bala, Santanu Dey, Kalpesh J. Haria +1

The characteristic function of row contractions and the characteristic function of liftings of row contractions are multi-analytic operators which are complete invariants up to uni…

math.FA2020

Commuting row contractions with polynomial characteristic functions

Monojit Bhattacharjee, Kalpesh J. Haria, Jaydeb Sarkar

A characteristic function is a special operator-valued analytic function defined on the open unit ball of $C^{n}$ associated with an $n$ -tuple of commuting row contraction o…

math.FA2017

Isometric dilations and von Neumann inequality for a class of tuples in the polydisc

Sibaprasad Barik, B. Krishna Das, Kalpesh J. Haria +1

The celebrated Sz.-Nagy and Foias and Ando theorems state that a single contraction, or a pair of commuting contractions, acting on a Hilbert space always possesses isometric dilat…

math.FA2016

Factorizations of Characteristic Functions

Kalpesh J. Haria, Amit Maji, Jaydeb Sarkar

Let $A = (A_{1}, \dots, A_{n})$ and $B = (B_{1}, \dots, B_{n})$ be row contractions on $H_{1}$ and $H_{2}$ , respectively, and $X$ be a row operator from $\oplus_{i=1}^n \…

math.OA2014

Functional Models and Minimal Contractive Liftings

Santanu Dey, Rolf Gohm, Kalpesh J. Haria

Based on a careful analysis of functional models for contractive multi-analytic operators we establish a one-to-one correspondence between unitary equivalence classes of minimal co…

math.OA2012

Outgoing Cuntz Scattering System for a Coisometric Lifting and Transfer Function

Kalpesh J. Haria

We study a coisometry that intertwines Popescu's presentations of minimal isometric dilations of a given operator tuple and of a coisometric lifting of the tuple. Using this we dev…

math.OA2011

Generalized repeated interaction model and transfer functions

Santanu Dey, Kalpesh J. Haria

Using a scheme involving a lifting of a row contraction we introduce a toy model of repeated interactions between quantum systems. In this model there is an outgoing Cuntz scatteri…

Regularity of the Sz.-Nagy and Foiaş Factorization of Characteristic Functions and Its Multivariable Analogue

k-Regular Factorizations and Joint Invariant Subspaces of Completely Non-Coisometric Row Contractions

k-Regular Factorizations and Invariant Subspaces of Completely Non-Unitary Contractions

Characteristic Functions and Colligations

Commuting row contractions with polynomial characteristic functions

Isometric dilations and von Neumann inequality for a class of tuples in the polydisc

Factorizations of Characteristic Functions

Functional Models and Minimal Contractive Liftings

Outgoing Cuntz Scattering System for a Coisometric Lifting and Transfer Function

Generalized repeated interaction model and transfer functions

$k$ -Regular Factorizations and Joint Invariant Subspaces of Completely Non-Coisometric Row Contractions

$k$ -Regular Factorizations and Invariant Subspaces of Completely Non-Unitary Contractions