Fredholm theory for demicompact linear relations

• Ammar, Aymen ^[1] ; Fakhfakh, Slim ^[1] ; Jeribi, Aref ^[1]
  1. [1] University of Sfax

     University of Sfax

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• Localización: Applied general topology, ISSN-e 1989-4147, ISSN 1576-9402, Vol. 23, Nº. 2, 2022, págs. 425-436
• Idioma: inglés
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• Resumen

  • We first attempt to determine conditions on a linear relation T such that μT becomes a demicompact linear relation for each μ ∈ [0,1)(see Theorems 2.4 and 2.5). Second, we display some results on Fredholm and upper semi-Fredholm linear relations involving a demicompact one(see Theorems 3.1 and 3.2). Finally, we provide some results in which a block matrix of linear relations becomes a demicompact block matrix of linear relations (see Theorems 4.2 and 4.3).