English

The iterated Aluthge Transforms of compact operators

Functional Analysis 2026-05-05 v2

Abstract

Let TT be a bounded linear operator on a Hilbert space. Then the Aluthge transform ΔT\Delta T and the sequence (ΔnT)(\Delta^nT) of Aluthge iterates of TT are defined by \begin{align*} \Delta T=|T|^{1/2}U|T|^{1/2},\,\Delta^0T=T,\,\Delta^nT=\Delta(\Delta^{n-1}T),\,n\in\mathbb{N}. \end{align*} We prove that Δ\Delta is a continuous map on the space of all compact operators on a separable Hilbert space with respect to the norm topology and using this result we also prove that the sequence (ΔnT)(\Delta^nT) converges in the norm topology to a normal compact operator for every compact operator TT on a separable Hilbert space. This gives an affirmative answer to two questions raised by Jung, Ko and Pearcy \cite{Pearcy2} for compact operators.

Keywords

Cite

@article{arxiv.2602.07916,
  title  = {The iterated Aluthge Transforms of compact operators},
  author = {Neeru Bala},
  journal= {arXiv preprint arXiv:2602.07916},
  year   = {2026}
}

Comments

An error in the result 2.2

R2 v1 2026-07-01T10:26:38.919Z