24 citations · 52 across the 25 of their papers we have counts for
26 papers
Bishop-like theorems for non-subnormal operators
Zenon Jan Jabłoński, Il Bong Jung, Jan Stochel
The celebrated Bishop theorem states that an operator is subnormal if and only if it is the strong limit of a net (or a sequence) of normal operators. By the Agler-Stankus theorem,…
Convergence of power sequences of operators via their stability
Zenon Jan Jabłoński, Il Bong Jung, Carlos Kubrusly +1
This paper is concerned with the convergence of power sequences and stability of Hilbert space operators, where "convergence" and "stability" refer to weak, strong and norm topolog…
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…
Convergence of power sequences of B-operators with applications to stability
Sameer Chavan, Zenon Jan Jabłoński, Il Bong Jung +1
The B-operators (abbreviation for Brownian-type operators) are upper triangular 2x2 block matrix operators that satisfy certain algebraic constraints. The purpose of this paper is…
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…
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…