令H是无限维的Hilbert空间,B(H)是H上有界线性算子的全体构成的集合。称算子T ∈ B(H)满足Browder定理,若σ(T)\ σw(T)⊆π00(T)或σw(T)=σb(T),其中 σ(T),σw(T),σb(T)分别表示算子 T 的谱集、Weyl 谱、Browder谱,π00(T)={λ∈ isoσ(T):0<dimN(T-λI)<∞}。借助新的谱集,给出有界线性算子及其函数满足Browder定理的等价条件。
Judgement of Browder's Theorem for Bounded Linear Operators and Their Functions
Let H be an infinite dimensional Hilbert space and B(H)be the algebra of all bounded linear operators on H.T ∈ B(H)satisfies the Browder's theorem if σ(T)\ σw(T)⊆π00(T)or σw(T)=σb(T),where σ(T),σw(T),σb(T)denote the spectrum,Weyl spectrum,Browder spectrum,and π00(T)={λ ∈ isoσ(T):0<dimN(T-λI)<∞}.In this paper,we establish for bounded linear operators and their functions the equivalent conditions for which Browder's theorem holds by a new spectrum.