On the axiomatic theory of spectrum
Tom 119 / 1996
Studia Mathematica 119 (1996), 109-128
DOI: 10.4064/sm-119-2-109-128
Streszczenie
There are a number of spectra studied in the literature which do not fit into the axiomatic theory of Żelazko. This paper is an attempt to give an axiomatic theory for these spectra, which, apart from the usual types of spectra, like one-sided, approximate point or essential spectra, include also the local spectra, the Browder spectrum and various versions of the Apostol spectrum (studied under various names, e.g. regular, semiregular or essentially semiregular).