34 citations · 34 across the 3 of their papers we have counts for
3 papers
math.FA2005
Perturbations of operators similar to contractions and the commutator equation
Catalin Badea
Let and be two Hilbert space contractions and let be a linear bounded operator. It was proved by C. Foias and J.P. Williams that in certain cases the operator block mat…
math.FA2005★ 34 cited
Constrained von Neumann inequalities
Catalin Badea, Gilles Cassier
An equivalent formulation of the von Neumann inequality states that the backward shift on is extremal, in the sense that if is a Hilbert space contraction, the…
math.FA2005
Schur multipliers and operator-valued Foguel-Hankel operators
Catalin Badea, Vern I. Paulsen
We show that some matrices are Schur multipliers and this is applied to obtain classes of operator-valued Foguel-Hankel operators similar to contractions. This provides partial ans…