Displaying similar documents to “On the spectrum of ψ -contracting operators.”

On the axiomatic theory of spectrum

V. Kordula, V. Müller (1996)

Studia Mathematica

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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).

The Słodkowski spectra and higher Shilov boundaries

Vladimír Müller (1993)

Studia Mathematica

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We investigate relations between the spectra defined by Słodkowski [14] and higher Shilov boundaries of the Taylor spectrum. The results generalize the well-known relation between the approximate point spectrum and the usual Shilov boundary.