English

A sufficient condition for the similarity of a polynomially bounded operator to a contraction

Functional Analysis 2019-06-04 v1

Abstract

Let TT be a polynomially bounded operator, and let M\mathcal M be its invariant subspace. Suppose that PMTMP_{\mathcal M^\perp}T|_{\mathcal M^\perp} is similar to a contraction, while θ(TM)=0\theta(T|_{\mathcal M})=0, where θ\theta is a finite product of Blaschke products with simple zeros satisfying the Carleson interpolating condition (a Carleson--Newman Blaschke product). Then TT is similar to a contraction. It is mentioned that Le Merdy's example shows that the assumption of polynomially boundedness cannot be replaced by the assumption of power boundedness.

Keywords

Cite

@article{arxiv.1803.10174,
  title  = {A sufficient condition for the similarity of a polynomially bounded operator to a contraction},
  author = {Maria Gamal'},
  journal= {arXiv preprint arXiv:1803.10174},
  year   = {2019}
}

Comments

Translated from Zapiski nauchn. semin. POMI, v. 456, 2017