WEYL TYPE-THEOREMS FOR DIRECT SUMS
WEYL TYPE-THEOREMS FOR DIRECT SUMS
The aim of this paper is to study the Weyl type-theorems for the orthogonal direct sum <TEX>$S{\oplus}T$</TEX>, where S and T are bounded linear operators acting on a Banach space X. Among other results, we prove that if both T and S possesses property (<TEX>$gb$</TEX>) and if <TEX>${\Pi}(T){\subset}{\sigma}_a(S)$</TEX>, <TEX>${\PI}(S){\subset}{\sigma}_a(T)$</TEX>, then …