12 citations · 12 across the 4 of their papers we have counts for
4 papers
Unitarily invariant norms
Stephan Ramon Garcia, Javad Mashreghi, Marek Ptak +1
This survey paper provides a comprehensive study of unitarily invariant norms on the algebra of matrices. This investigation leads naturally to the theory of symmetric…
Conjugations of Unitary Operators, II
Javad Mashreghi, Marek Ptak, William T. Ross
For a given unitary operator on a separable complex Hilbert space $\h$, we describe the set of all conjugations (antilinear, isometric, and involutive…
Conjugations of Unitary operators, I
Javad Mashreghi, Marek Ptak, William T. Ross
If is a unitary operator on a separable complex Hilbert space , an application of the spectral theorem says there is a conjugation on (an antilin…
Analytic structure of weighted shifts on directed trees
Piotr Budzynski, Piotr Dymek, Marek Ptak
We show that a weighted shift on a directed tree is related to a multiplier algebra of coefficients of analytic functions. We use this relation to study spectral properties of the…