Generalized Drazin-type spectra of Operator matrices.

• Autores: A. Tajmouati, M. Abkari, M. Karmouni
• Localización: Proyecciones: Journal of Mathematics, ISSN 0716-0917, ISSN-e 0717-6279, Vol. 37, Nº. 1, 2018, págs. 119-131
• Idioma: inglés
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• Resumen

  • In this paper, we investigate the limit points set of surjective and approximate point spectra of upper triangular operator matrices . We prove that σ*(MC) ∪ W=σ*(A)∪ σ*(B) where W is the union of certain holes in σ*(MC), which happen to be subsets of σ lgD(B) ∩ σrgD(A), σ* ∈ {σlgD, σrgD}  are the limit points set of surjective and approximate point spectra. Furthermore, several sufficient conditions for σ* (MC) = σ* (A)∪σ* (B) holds for every C ∈ ℬ(Y,X) are given.