文摘
A Banach space operator satisfies Browder's theorem if the complement of the Weyl spectrum σw(T) of T in σ(T) equals the set of Riesz points of T; T is polaroid if the isolated points of σ(T) are poles (no restriction on rank) of the resolvent of T. Let Φ(T) denote the set of Fredholm points of T. Browder's theorem transfers from to S=LARB (resp., S=AB) if and only if A and B* (resp., A and B) have SVEP at points μΦ(A) and νΦ(B) for which λ=μνσw(S). If A and B are finitely polaroid, then the polaroid property transfers from and to LARB; again, restricting ourselves to the completion of in the projective topology, if A and B are finitely polaroid, then the polaroid property transfers from and to AB.