English

Convergence of iterated Aluthge transform sequence for diagonalizable matrices II: $\lambda$-Aluthge transform

Functional Analysis 2007-06-11 v1

Abstract

Let λ(0,1)\lambda \in (0,1) and let TT be a r×rr\times r complex matrix with polar decomposition T=UTT=U|T|. Then, the \la\la- Aluthge transform is defined by Δλ(T)=TλUT1λ. \Delta_\lambda (T )= |T|^{\lambda} U |T |^{1-\lambda}. Let Δλn(T)\Delta_\lambda^{n}(T) denote the n-times iterated Aluthge transform of TT, nNn\in\mathbb{N}. We prove that the sequence {Δλn(T)}nN\{\Delta_\lambda^{n}(T)\}_{n\in\mathbb{N}} converges for every r×rr\times r {\bf diagonalizable} matrix TT. We show regularity results for the two parameter map (\la,T)\alulitT(\la, T) \mapsto \alulit{\infty}{T}, and we study for which matrices the map (0,1)λΔλ(T)(0,1)\ni \lambda \mapsto \Delta_\lambda^{\infty}(T) is constant.

Keywords

Cite

@article{arxiv.0706.1234,
  title  = {Convergence of iterated Aluthge transform sequence for diagonalizable matrices II: $\lambda$-Aluthge transform},
  author = {Jorge Antezana and Enrique Pujals and Demetrio Stojanoff},
  journal= {arXiv preprint arXiv:0706.1234},
  year   = {2007}
}
R2 v1 2026-06-21T08:36:42.374Z