English

On the B-discrete spectrum

Spectral Theory 2019-07-19 v4

Abstract

In this paper, we introduce the B-discrete spectrum of an unbounded closed operator and we prove that a closed operator has a purely B-discrete spectrum if and only if it has a meromorphic resolvent. After that, we study the stability of the B-discrete spectrum under several type of perturbations and we establish that two closed invertible linear operators having quasisimilar totally paranormal inverses have equal spectra and B-discrete spectra.

Keywords

Cite

@article{arxiv.1606.03712,
  title  = {On the B-discrete spectrum},
  author = {Mohammed Berkani},
  journal= {arXiv preprint arXiv:1606.03712},
  year   = {2019}
}

Comments

10 pages

R2 v1 2026-06-22T14:23:25.744Z