Spectral theory for polynomially demicompact operators

Fatma Brahim, Aref Jeribi, Bilel Krichen
2019 Filomat  
In this article, we introduce the notion of polynomial demicompactness and we use it to give some results on Fredholm operators and to establish a fine description of some essential spectra of a closed densely defined linear operator. Our work is a generalization of many known ones in the literature.
doi:10.2298/fil1907017b fatcat:tqerq7pflrfstbrqia2ufv5d3a