研究了Hilbert空间上有界线性算子及其共轭算子的(ω)性质的等价性.通过算子T的一致可逆谱集σCI(T)和一致Fredholm指标谱集σCFI(T)之间的关系,证明了:T与T*同时有(ω1)性质当且仅当σCI(T)=σCFI(T),而且Browder定理对T成立;T与T*同时有(ω)性质且isoloid的当且仅当σCI(T)=σCFI(T),而且σb(t)=σ3(T)∪■∪{λ∈C:n(T-λI)=n(T*-λI)=∞},其中σ3(T)为半Fredholm谱的一种变化.同时研究了算子摄动的(ω)性质的等价性.
The judgement of equivalence for property(ω) between an operator and its conjugate on a Hilbert space is discussed.By the relation between the two new spectrum sets σCI(T) and σCFI(T) defined in view of the consistency in invertibility and in the Fredholm index respectively,the following two conclusions are proved.First,both T and its conjugate T* satisfy property(ω1) if and only if σCI(T)=σCFI(T) and Browder's theorem holds for T;second,both T and its conjugate T* satisfy property(ω) and are all isoloid if and only if σCI(T)=σCFI(T) and σb(T)=σ3(T)∪■∪{λ∈C:n(T-λT)=n(T*-λI)=∞},where σ3(T) is a variant of semi-Fredholm spectrum.Also,the equivalence for the perturbation of property(ω) is considered.