Approximation of Hilbert Space Operators, 第 1 卷

analytic Cauchy domain Apostol approximation argument Banach Banach space C. M. Pearcy C*-algebra C₁ Calkin algebra clopen subset closure commuting compact operator compact perturbation completely apparent component Corollary 3.22 D. A. Herrero decomposition defined denote dense denumerable diagonal dimensional space dist[A easily seen finite dimensional finite rank operator fortiori Fredholm operator function given H₁ Hence hermitian Hilbert space infinite invertible Jordan nilpotent K₁ L(cd Lemma M+(T Math matrix n-tuple N₁ nest nice Jordan nilpotent nilpotent operators normal operator numbers obtain operator acting orthogonal projection Otre p₁ P₂ polynomial proof of Theorem Proposition quasinilpotent operator quasitriangular R₁ readily follows resp result satisfies semi-Fredholm semi-Fredholm operator similarity orbits spectral spectrum T₁ T₂ Theorem 5.1 triangular operator unitarily equivalent unitary operator vector Voiculescu