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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2017 Volume 456, Pages 77–95 (Mi znsl6422)

This article is cited in 1 paper

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

M. F. Gamal'

St. Petersburg Department of Steklov Mathematical Institute of Russian Academy of Sciences, St. Petersburg, Russia

Abstract: Let $T$ be a polynomially bounded operator, and let $\mathcal M$ be its invariant subspace. Suppose that $P_{\mathcal M^\perp}T|_{\mathcal M^\perp}$ is similar to a contraction, while $\theta(T|_\mathcal M)=0$, where $\theta$ is a finite product of Blaschke products with simple zeros satisfying the Carleson interpolating condition. Then $T$ 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.

Key words and phrases: polynomially bounded operator, similarity, contraction, $C_0$-operator, Carleson interpolating condition.

UDC: 517.98

Received: 22.05.2017


 English version:
Journal of Mathematical Sciences (New York), 2018, 234:3, 318–329


© Steklov Math. Inst. of RAS, 2024