On the Perturbation of the Spectra of Kato Upper Triangular Operator Matrices
Tian Junhong, Xiaohong Cao
Abstract
Tian Junhong, Xiaohong Cao
Abstract
Letσ_2(A) =σ_e(A)∪σ_k(A) U{λ∈C:ind(A-λI) 0},whereσ_e(A) andσ_k(A) denote the essential spectrum and Kato spectrum of an operator A,respectively.In thispaper,using the relation between the nullity and the defect of a given pair operators,we studythe perturbation of the spectrumσ_2(-) for upper triangular operator matrices.
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Letσ_2(A) =σ_e(A)∪σ_k(A) U{λ∈C:ind(A-λI) 0},whereσ_e(A) andσ_k(A) denote the essential spectrum and Kato spectrum of an operator A,respectively.In thispaper,using the relation between the nullity and the defect of a given pair operators,we studythe perturbation of the spectrumσ_2(-) for upper triangular operator matrices.
Key concepts: Mathematics, Operator matrix, Perturbation (astronomy), Spectrum (functional analysis), Operator (biology), Triangular matrix, Eigenvalues and eigenvectors, Spectral line