부산대학교 도서관

Let ℋ{\mathcal{ {\mathcal H} }} be an infinite dimensional complex Hilbert space and ℬ(ℋ){\mathcal{ {\mathcal B} }}\left({\mathcal{ {\mathcal H} }}) the algebra of all bounded linear operators on ℋ{\mathcal{ {\mathcal H} }}. For an operator T∈ℬ(ℋ)T\in {\mathcal{ {\mathcal B} }}\left({\mathcal{ {\mathcal H} }}), we say property (t)\left(t) holds for TT if σ(T)⧹σuw(T)=Π00(T)\sigma \left(T)\hspace{-0.08em}\setminus \hspace{-0.08em}{\sigma }_{uw}\left(T)={\Pi }_{00}\left(T), where σ(T)\sigma \left(T) and σuw(T){\sigma }_{uw}\left(T) denote the spectrum and the Weyl essential approximate point spectrum of TT, respectively, and Π00(T)={λ∈isoσ(T):0