5 papers · 1 filter
The operator-valued Schur-Agler class in infinitely many variables
Shubham Rastogi, Chaman Kumar Sahu
Motivated by a recent work of G. Knese [Canad. Math. Bull., 2026], we introduce the operator-valued Schur-Agler class in infinitely many variables, consisting of functions whose re…
Isometric rigidity of complete Pick algebras on monomial varieties
Hamidul Ahmed, B. Krishna Das, Chaman Kumar Sahu
We establish a geometric rigidity theorem for a class of monomial varieties in finite-dimensional unit balls. Every ball automorphism mapping one such variety onto another is unita…
Noncommutative Marcus-Ree inequality and Erdős channels
Repana Devendra, Chaman Kumar Sahu
Unital quantum channels are the noncommutative analogues of doubly stochastic matrices. In 1959, Marcus and Ree showed that the squared Frobenius norm of a doubly stochastic matrix…
Unbounded Toeplitz operators and finite rank de Branges-Rovnyak spaces
Soumitra Ghara, MD Ramiz Reza, Chaman Kumar Sahu
Motivated by the recent developments of de Branges-Rovnyak spaces, we investigate the function theoretic aspects of finite rank de Branges-Rovnyak spaces generated by row-va…
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…