Quasi-Fredholm spectrum for operator matrices
نویسندگان
چکیده
For A ? L(X), B L(Y) and C L(Y,X) we denote by MC the operator matrix defined on X Y = (A 0 B). In this paper, prove that ?qF(A) ?qF(B) [ C?L(Y,X) ?qF(MC) ?p(B) ?p(A?), where ?qF(.) (resp. ?p(.)) denotes quasi-Fredholm spectrum point spectrum). Furthermore, consider some sufficient conditions for to be have ?qF(MC).
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ژورنال
عنوان ژورنال: Filomat
سال: 2022
ISSN: ['2406-0933', '0354-5180']
DOI: https://doi.org/10.2298/fil2214893e