English

On power bounded operators with holomorphic eigenvectors, II

Functional Analysis 2023-03-31 v1

Abstract

In [U] (among other results), M. Uchiyama gave the necessary and sufficient conditions for contractions to be similar to the unilateral shift SS of multiplicity 11 in terms of norm-estimates of complete analytic families of eigenvectors of their adjoints. In [G2], it was shown that this result for contractions can't be extended to power bounded operators. Namely, a cyclic power bounded operator was constructed which has the requested norm-estimates, is a quasiaffine transform of SS, but is not quasisimilar to SS. In this paper, it is shown that the additional assumption on a power bounded operator to be quasisimilar to SS (with the requested norm-estimates) does not imply similarity to SS. A question whether the criterion for contractions to be similar to SS can be generalized to polynomially bounded operators remains open. Also, for every cardinal number 2N2\leq N\leq \infty a power bounded operator TT is constructed such that TT is a quasiaffine transform of SS and dimkerT=N\dim\ker T^*=N. This is impossible for polynomially bounded operators. Moreover, the constructed operators TT have the requested norm-estimates of complete analytic families of eigenvectors of TT^*.

Keywords

Cite

@article{arxiv.1901.03883,
  title  = {On power bounded operators with holomorphic eigenvectors, II},
  author = {Maria F. Gamal'},
  journal= {arXiv preprint arXiv:1901.03883},
  year   = {2023}
}
R2 v1 2026-06-23T07:09:47.877Z