3 papers
math.FA2026
Foguel-type operators similar to contractions
Nilanjan Das, Soma Das, Jaydeb Sarkar
Pisier's celebrated counterexample to Halmos's similarity-to-contractions problem was based on upper triangular block operator matrices involving three classical opera…
math.FA2025
Invariant subspaces of Brownian shifts on vector-valued Hardy spaces
Nilanjan Das, Soma Das, Jaydeb Sarkar
We characterize invariant subspaces of Brownian shifts on vector-valued Hardy spaces. We also solve the unitary equivalence problem for the invariant subspaces of these shifts.
math.PR2025
Invariant subspaces and the -property of Brownian Shifts
Nilanjan Das, Soma Das, Jaydeb Sarkar
We consider the restriction of Brownian shifts to their invariant subspaces and classify when they are unitarily equivalent. Additionally, we prove an asymptotic property stating t…