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Bounded Point Evaluations For Rationally Multicyclic Subnormal Operators

Functional Analysis 2017-11-01 v1

Abstract

Let SS be a pure bounded rationally multicyclic subnormal operator on a separable complex Hilbert space H\mathcal H and let MzM_z be the minimal normal extension on a separable complex Hilbert space K\mathcal K containing H.\mathcal H. Let bpe(S)bpe(S) be the set of bounded point evaluations and let abpe(S)abpe(S) be the set of analytic bounded point evaluations. We show abpe(S)=bpe(S)Int(σ(S)).abpe(S) = bpe(S) \cap Int(\sigma (S)). The result affirmatively answers a question asked by J. B. Conway concerning the equality of the interior of bpe(S)bpe(S) and abpe(S)abpe(S) for a rationally multicyclic subnormal operator S.S. As a result, if λ0Int(σ(S))\lambda_0\in Int(\sigma (S)) and dim(ker(Sλ0))=N,dim(ker(S-\lambda_0)^*) = N, where NN is the minimal number of cyclic vectors for S,S, then the range of Sλ0S-\lambda_0 is closed, hence, λ0σ(S)σe(S).\lambda_0 \in \sigma (S) \setminus \sigma_e (S).

Keywords

Cite

@article{arxiv.1710.11265,
  title  = {Bounded Point Evaluations For Rationally Multicyclic Subnormal Operators},
  author = {Liming Yang},
  journal= {arXiv preprint arXiv:1710.11265},
  year   = {2017}
}

Comments

11 pages

R2 v1 2026-06-22T22:30:37.649Z