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Invariant subspaces of perturbed backward shift

Functional Analysis 2024-08-09 v2 Complex Variables Operator Algebras

Abstract

We represent closed subspaces of the Hardy space that are invariant under finite-rank perturbations of the backward shift. We apply this to classify almost invariant subspaces of the backward shift and represent a more refined version of nearly invariant subspaces. Kernels of certain perturbed Toeplitz operators are examples of the newly introduced nearly invariant subspaces.

Keywords

Cite

@article{arxiv.2407.17352,
  title  = {Invariant subspaces of perturbed backward shift},
  author = {Soma Das and Jaydeb Sarkar},
  journal= {arXiv preprint arXiv:2407.17352},
  year   = {2024}
}

Comments

26 pages. revised and corrected

R2 v1 2026-06-28T17:52:28.259Z