On the equations X=KXS and AX=XK
Peter Rosenthal (1982)
Banach Center Publications
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Peter Rosenthal (1982)
Banach Center Publications
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Takeshi Miura, Dai Honma (2009)
Open Mathematics
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Let A and B be standard operator algebras on Banach spaces X and Y, respectively. The peripheral spectrum σπ (T) of T is defined by σπ (T) = z ∈ σ(T): |z| = maxw∈σ(T) |w|. If surjective (not necessarily linear nor continuous) maps φ, ϕ: A → B satisfy σπ (φ(S)ϕ(T)) = σπ (ST) for all S; T ∈ A, then φ and ϕ are either of the form φ(T) = A 1 TA 2 −1 and ϕ(T) = A 2 TA 1 −1 for some bijective bounded linear operators A 1; A 2 of X onto Y, or of the form φ(T) = B 1 T*B 2 −1 and ϕ(T) = B 2 T*B...
W. Żelazko, Z. Słodkowski (1974)
Studia Mathematica
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V. Müller (1997)
Studia Mathematica
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We construct a pair of commuting Banach space operators for which the splitting spectrum is different from the Taylor 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).
Andrzej Sołtysiak (1989)
Colloquium Mathematicae
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Marcin Bownik, John Jasper (2015)
Bulletin of the Polish Academy of Sciences. Mathematics
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Given a finite set X⊆ ℝ we characterize the diagonals of self-adjoint operators with spectrum X. Our result extends the Schur-Horn theorem from a finite-dimensional setting to an infinite-dimensional Hilbert space analogous to Kadison's theorem for orthogonal projections (2002) and the second author's result for operators with three-point spectrum (2013).
Muneo Chō, Makoto Takaguchi (1981)
Studia Mathematica
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Gh. Constantin (1975)
Matematički Vesnik
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Ragimov, Misir B. (2003)
Bulletin of the Malaysian Mathematical Sciences Society. Second Series
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Volker Wróbel (1986)
Studia Mathematica
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T. Mouton, H. Raubenheimer (1993)
Studia Mathematica
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We give a spectral characterisation of rank one elements and of the socle of a semisimple Banach algebra.
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.