English

Spectral enclosures for a class of block operator matrices

Spectral Theory 2020-06-02 v2

Abstract

We prove new spectral enclosures for the non-real spectrum of a class of 2×22\times2 block operator matrices with self-adjoint operators AA and DD on the diagonal and operators BB and B-B^* as off-diagonal entries. One of our main results resembles Gershgorin's circle theorem. The enclosures are applied to JJ-frame operators.

Keywords

Cite

@article{arxiv.1903.01519,
  title  = {Spectral enclosures for a class of block operator matrices},
  author = {Juan Giribet and Matthias Langer and Francisco Martínez Pería and Friedrich Philipp and Carsten Trunk},
  journal= {arXiv preprint arXiv:1903.01519},
  year   = {2020}
}
R2 v1 2026-06-23T07:58:04.681Z