Extended Weyl-type theorems for direct sums

• Autorzy: Berkani M. , Kachad M. , Zariouh H.
• Języki publikacji: EN

Abstrakty

EN

In this paper, we study the stability of extended Weyl and Browdertype theorems for orthogonal direct sum (...), where S and T are bounded linear operators acting on Banach space. Two counterexamples shows that property (ab), in general, is not preserved under direct sum. Nonetheless, and under the assumptions that (…), we characterize preservation of property (ab) under direct sum (...). Furthermore, we show that if S and T satisfy generalized a-Browder’s theorem, then (...) satisfies generalized a-Browder’s theorem if and only if (…), which improves a recent result of [13] by removing certain extra assumptions.

Słowa kluczowe

EN

property (gab); property (gaw); direct sum; B-Weyl spectrum

PL

własność (GAB); własność (GAW); suma prosta; widmo B-Weyla

• Wydawca: De Gruyter
• Czasopismo: Demonstratio Mathematica
• Rocznik: 2014
• Tom: Vol. 47, nr 2
• Strony: 411--422
• Opis fizyczny: Bibliogr. 18 poz.

Twórcy

autor

Berkani M.

• Department of Mathematics, Science Faculty of Oujda University, Mohammed I Operator Theory Team, Morocco

autor

Kachad M.

• Department of Mathematics, Science Faculty of Oujda University, Mohammed I Operator Theory Team, Morocco

autor

Zariouh H.

• Centre Régional Des Métiers De L’éducarion Et De Formation B.P 458, Oujda, Marocco
• Equipe De La Théorie Des Opérateurs, Université Mohammed I, Faculté Des Sciences D’oujda Dépt. De Mathematiques, Marocco

Bibliografia

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