For A ? L(X), B ? L(Y) and C ? L(Y,X) we denote by MC the operator matrix
defined on X ? Y by MC = (A C 0 B). In this paper, we prove that ?qF(A) ?
?qF(B) ? [ C?L(Y,X) ?qF(MC) ? ?p(B) ? ?p(A?), where ?qF(.) (resp. ?p(.))
denotes the quasi-Fredholm spectrum (resp. the point spectrum). Furthermore,
we consider some sufficient conditions for MC to be quasi-Fredholm and
sufficient conditions to have ?qF(A) ? ?qF(B) = ? C?L(Y,X) ?qF(MC).
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