Golichev, I. I. Approximation of an element in the range of a function of an operator. (English. Russian original) Zbl 0426.41019 Sov. Math., Dokl. 20, 318-321 (1979); translation from Dokl. Akad. Nauk SSSR 245, 527-530 (1979). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page MSC: 41A35 Approximation by operators (in particular, by integral operators) 30E10 Approximation in the complex plane 41A65 Abstract approximation theory (approximation in normed linear spaces and other abstract spaces) 47A55 Perturbation theory of linear operators Keywords:approximation of an element in the range of a function of an operator; linear combinations of eigenvalues PDF BibTeX XML Cite \textit{I. I. Golichev}, Sov. Math., Dokl. 20, 318--321 (1979; Zbl 0426.41019); translation from Dokl. Akad. Nauk SSSR 245, 527--530 (1979)