Dr Hedi BENKHALED, Dr Srar ELLEUCH, Professor DR.

Uniformly continuous cosine families properties around weak demicompactness concept

Anahtar Kelimeler:

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

Uniformly continuous cosine families properties around weak demicompactness concept

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.

Keywords:

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

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