On the o-Spectrum of Order Bounded Operators.
Helmut H. Schaefer (1977)
Mathematische Zeitschrift
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Helmut H. Schaefer (1977)
Mathematische Zeitschrift
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Ulrich Groh (1981)
Mathematische Zeitschrift
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Gh. Constantin (1975)
Matematički Vesnik
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Bucur, Amelia (1996)
General Mathematics
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V. Rakočević (1985)
Matematički Vesnik
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Benharrat, Mohammed, Messirdi, Bekkai (2011)
Serdica Mathematical Journal
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2010 Mathematics Subject Classification: 47A10. We show that the symmetric difference between the generalized Kato spectrum and the essential spectrum defined in [7] by sec(T) = {l О C ; R(lI-T) is not closed } is at most countable and we also give some relationship between this spectrum and the SVEP theory.
Johann Walter (1972)
Mathematische Zeitschrift
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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).
Derek Kitson (2009)
Studia Mathematica
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We extend the notion of ascent and descent for an operator acting on a vector space to sets of operators. If the ascent and descent of a set are both finite then they must be equal and give rise to a canonical decomposition of the space. Algebras of operators, unions of sets and closures of sets are treated. As an application we construct a Browder joint spectrum for commuting tuples of bounded operators which is compact-valued and has the projection property.
W. Młak (1990)
Annales Polonici Mathematici
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S. Djordjević, B. Duggal (2000)
Studia Mathematica
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We show that p-hyponormal operators obey Weyl's and a-Weyl's theorem. Also, we show that the spectrum, Weyl spectrum, Browder spectrum and approximate point spectrum are continuous functions in the class of all p-hyponormal operators.
Djordjević, Slaviša V. (1997)
Matematichki Vesnik
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Günter Stolz (1991)
Journal für die reine und angewandte Mathematik
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