24 citations · 80 across the 39 of their papers we have counts for
4 papers · 1 filter
Weakly concave operators
Sameer Chavan, Jan Stochel
We study a class of left-invertible operators which we call weakly concave operators. It includes the class of concave operators and some subclasses of expansive strict -isometr…
Conditionally positive definite unilateral weighted shifts
Zenon Jan Jabłoński, Il Bong Jung, Eun Young Lee +1
In a recent paper [15], Hilbert space operators with the property that each sequence of the form is conditionally positive definite in a semigr…
Two-moment characterization of spectral measures on the real line
Paweł Pietrzycki, Jan Stochel
Kiukas, Lahti and Ylinen asked the following general question. When is a positive operator measure projection valued? A version of this question formulated in terms of operator mom…
On th roots of bounded and unbounded quasinormal operators
Paweł Pietrzycki, Jan Stochel
In a recent paper [9], R. E. Curto, S. H. Lee and J. Yoon asked the following question: Let be a subnormal operator, and assume that is quasinormal. Does it follow that $…