English

Dual-band general Toeplitz operators

Functional Analysis 2021-06-04 v2

Abstract

We relate dual-band general Toeplitz operators to block truncated Toeplitz operators and, via equivalence after extension, with Toeplitz operators with 4×44 \times 4 matrix symbols. We discuss their norm, their kernel, Fredhomlness, invertibility and spectral properties in various situations, focusing on the spectral properties of the dual-band shift, which turns out to be considerably complex, leading to new and nontrivial connections with the boundary behaviour of the associated inner function.

Keywords

Cite

@article{arxiv.2012.14725,
  title  = {Dual-band general Toeplitz operators},
  author = {M. Cristina Câmara and Ryan O'Loughlin and Jonathan R. Partington},
  journal= {arXiv preprint arXiv:2012.14725},
  year   = {2021}
}

Comments

30 pages. Title changed from the previous version. Simpler proofs found for some of the later results

R2 v1 2026-06-23T21:33:08.936Z