8 papers · 1 filter
Finite sum of squares, finite realization and noncommutative Carathéodory approximation
Tirthankar Bhattacharyya, James Eldred Pascoe, Chandan Pradhan
In the noncommutative polydisc, we first prove a positive sum of squares formula for a non-negative hereditary rational nc-function. The number of summands is finite. This result i…
Multiplicative linear functionals on reproducing kernel Hilbert spaces
Tirthankar Bhattacharyya, Jaikishan, Poornendu Kumar +1
The classical Gleason--Kahane--Zelazko theorem characterizes multiplicative linear functionals on a unital Banach algebra through the scalar identity . We develo…
Hankel operators and Projective Hilbert modules on quotients of bounded symmetric domains
Tirthankar Bhattacharyya, Mainak Bhowmik, Haripada Sau
Consider a bounded symmetric domain with a finite pseudo-reflection group acting on it as a subgroup of the group of automorphisms. This gives rise to quotient domains by means…
Functions with image in a strip
Tirthankar Bhattacharyya, Anthony G. O'Farrell, Shubham Rastogi +1
We consider holomorphic functions on the unit disc whose images are contained in a strip of the complex plane. Under an additional condition, such functions are constants. We also…
Complete Nevanlinna-Pick Kernels and the Curvature Invariant
Tirthankar Bhattacharyya, Abhay Jindal
We consider a unitarily invariant complete Nevanlinna-Pick kernel denoted by and a commuting -tuple of bounded operators satisfying a natural con…
The Bishop-Phelps-Bollobas property for certain Banach spaces
Tirthankar Bhattacharyya, Mainak Bhowmik, Kousik Dhara
Let be a complex Banach space. We prove that if is an extremally disconnected compact Hausdorff topological space, then the pair satisfies the Bishop-Phelps-Bol…