Dergiler / Hacettepe Journal of Mathematics and Statistics / 2022 / Cilt: 51 - Sayı: 6

Uniformly continuous cosine families properties around weak demicompactness concept

Uniformly continuous cosine families properties around weak demicompactness concept

Dr Hedi BENKHALED, Dr Srar ELLEUCH, Professor DR.

Sayfa
1674–1679
DOI
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Abstract

In this paper, we use the concept of weak demicompactness in order to give some properties for the uniformly continuous cosine families. Our theoretical results will be illustrated by investigating the spectral inclusion for a uniformly continuous cosine family for an upper semi-Fredholm spectrum.

Anahtar kelimeler: cosine family, weakly demicompact operator, upper semi-Fredholm spectrum, spectral inclusion