Direct and Inverse Theorems in the Theory of Approximation by the Ritz Method

For an arbitrary self-adjoint operator B in a Hilbert space \(\mathfrak{H}\), we present direct and inverse theorems establishing the relationship between the degree of smoothness of a vector \(x \in \mathfrak{H}\) with respect to the operator B, the rate of convergence to zero of its best approxima...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Datum:2005
Hauptverfasser: Gorbachuk, M. L., Hrushka, Ya. I., Torba, S. M., Горбачук, М. Л., Грушка, Я. І., Торба, С. М.
Format: Artikel
Sprache:Ukrainisch
Englisch
Veröffentlicht: Institute of Mathematics, NAS of Ukraine 2005
Online Zugang:https://umj.imath.kiev.ua/index.php/umj/article/view/3629
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Назва журналу:Ukrains’kyi Matematychnyi Zhurnal
Завантажити файл: Pdf

Institution

Ukrains’kyi Matematychnyi Zhurnal
Beschreibung
Zusammenfassung:For an arbitrary self-adjoint operator B in a Hilbert space \(\mathfrak{H}\), we present direct and inverse theorems establishing the relationship between the degree of smoothness of a vector \(x \in \mathfrak{H}\) with respect to the operator B, the rate of convergence to zero of its best approximation by exponential-type entire vectors of the operator B, and the k-modulus of continuity of the vector x with respect to the operator B. The results are used for finding a priori estimates for the Ritz approximate solutions of operator equations in a Hilbert space.