IL Bong Jung

activity

20112026

collaborators

4 papers

math.FA2026

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 $L^{2} (μ)$ , where $μ$ is a discrete measure. Our main result shows that, for every integer $p \geq 2$ , there exists a non-hyponormal composition ope…

math.FA2026

CPD $n$ th roots of subnormal operators are subnormal

Zenon Jan Jabłoński, Il Bong Jung, Paweł Pietrzycki +1

We investigate the $n$ th root problem for bounded operators on a Hilbert space within the class of conditionally positive definite (CPD) operators determined by the Lévy--Khintchin…

math.FA2024

When is a CPD weighted shift similar to a subnormal operator?

Zenon Jan Jabłoński, Il Bong Jung, Jan Stochel

We prove that a CPD unilateral weighted shift $W_{λ}$ of type III is a quasi-affine transform of the operator $M_{z}$ of multiplication by the independent variable on the $L^{2} (ρ)$ -clos…

math.FA2011

A non-hyponormal operator generating Stieltjes moment sequences

Z. J. Jablonski, I. B. Jung, J. Stochel

A linear operator $S$ in a complex Hilbert space $\hh$ for which the set $\dzn{S}$ of its $C^{\infty}$ -vectors is dense in $\hh$ and ${∥ S^{n} f ∥^{2}}_{n = 0}^{\infty}$ is a Stieltjes mom…

Solutions to the 'moment property implies subnormality' and injectivity problems for composition operators on one-circuit graphs

CPD nth roots of subnormal operators are subnormal

When is a CPD weighted shift similar to a subnormal operator?

A non-hyponormal operator generating Stieltjes moment sequences

CPD $n$ th roots of subnormal operators are subnormal