摘要
设M_C表示Hilbert空间H_1⊕H_2上的上三角算子矩阵M_C=(ACOB),用∩_*表示∩_(C∈B(H_2,H_1))σ_*(M_C),其中*表示某类谱,称满足等式∩_*=σ_*(M_0)的谱为固零谱,本文集中给出上三角算子矩阵的三类固零谱,并举例说明谱等式σ_*(M_0)=σ_*(A)∪σ_*(B)对这三类固零谱失效.
Let M_C be an upper triangular operator matrix acting on a Hilbert space H_1⊕H_2, where M_C =(ACOB),we denote ∩_(C∈B(H_2,H_1))σ_*(M_C) by ∩_*,where * represents one kind of spectrum. In this paper, we present three kinds of spectrum in an unifying manner, and illustrates in examples that the common equality σ_*(MO) =σ_*(A)∪σ_*(B)is not valid for these spectrums.
引文
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