M Berkani, N Castro, SV Djordjevic - MATHEMATICA BOHEMICA, 2006 - emis.dsd.sztaki.hu
Let $ T $ be an operator acting on a Banach space $ X $, let $\sigma (T) $ and $\sigma_
{BW}(T) $ be respectively the spectrum and the B-Weyl spectrum of $ T $. We say that $ T …