24 citations · 51 across the 17 of their papers we have counts for
19 papers
Solutions to the 'moment property implies subnormality' and injectivity problems for composition operators on one-circuit graphs
Piotr Budzyński, Zenon Jan Jabłoński, Il Bong Jung +1
We consider composition operators in , where is a discrete measure. Our main result shows that, for every integer , there exists a non-hyponormal composition ope…
Criteria for algebraic operators to be unitary
Zenon Jan Jablonski, Il Bong Jung, Jan Stochel
Criteria for an algebraic operator on a complex Hilbert space to be unitary are established. The main one is written in terms of the convergence of sequences of t…
Lifting Brownian-type operators with subnormal entry
Sameer Chavan, Zenon Jan Jablonski, Il Bong Jung +1
In this paper, we study Brownian-type operators, which are upper triangular block matrix operators with entries satisfying some algebraic constraints. We establish a li…
m-isometric operators and their local properties
Z. J. Jablonski, I. B. Jung, J. Stochel
In this paper we give necessary and sufficient conditions for a bounded linear Hilbert space operator to be an -isometry for an unspecified written in terms of conditions th…
Subnormality of unbounded composition operators over one-circuit directed graphs: exotic examples
Piotr Budzynski, Zenon Jan Jablonski, Il Bong Jung +1
A recent example of a non-hyponormal injective composition operator in an -space generating Stieltjes moment sequences, invented by three of the present authors, was built ove…
Subnormal weighted shifts on directed trees whose nth powers have trivial domain
Piotr Budzynski, Zenon Jan Jablonski, Il Bong Jung +1
It is shown that for any positive integer n there exists a subnormal weighted shift on a directed tree whose nth power is closed and densely defined while its (n + 1)th power has t…