4 papers · 1 filter
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…
Paired and Toeplitz + Hankel operators
Nilanjan Das, Soma Das, Jaydeb Sarkar
We present complete classifications of Toeplitz + Hankel operators on vector-valued Hardy spaces and classify paired operators on . We also study the latter class…
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.
Invariant subspaces of perturbed backward shift
Soma Das, Jaydeb Sarkar
We represent closed subspaces of the Hardy space that are invariant under finite-rank perturbations of the backward shift. We apply this to classify almost invariant subspaces of t…