Some tidbits on ideal projectors, commuting matrices and their applications.
Statistical approximation properties of q-Baskakov-Kantorovich operators
In the present paper we introduce a q-analogue of the Baskakov-Kantorovich operators and investigate their weighted statistical approximation properties. By using a weighted modulus of smoothness, we give some direct estimations for error in case 0 < q < 1.
Strong unicity criterion in some space of operators
Let be a finite dimensional Banach space and let be a hyperplane. Let . In this note, we present sufficient and necessary conditions on being a strongly unique best approximation for given . Next we apply this characterization to the case of and to generalization of Theorem I.1.3 from [12] (see also [13]).
Symmetric subspaces of with large projection constants
We construct k-dimensional (k ≥ 3) subspaces of , with a very simple structure and with projection constant satisfying .
The Baskakov operators for functions of two variables.
The direct and converse inequalities for Jackson-type operators on spherical cap.
The discrete Fourier-Transform an Lp approximation of functions.
The strong unicity constant for projections.
Tractability of tensor product linear operators in weighted Hilbert spaces.
Trivariate approximation operators on cube by parametric extensions.
Two-dimensional real symmetric spaces with maximal projection constant
Let V be a two-dimensional real symmetric space with unit ball having 8n extreme points. Let λ(V) denote the absolute projection constant of V. We show that where is the space whose ball is a regular 8n-polygon. Also we reprove a result of [1] and [5] which states that for any two-dimensional real symmetric space V.
Über die Approximation unbeschränkter Funktionen durch lineare positive Operatoren.
Über Jackson- und Bernstein-Typ Ungleichungen für lineare Approximationsverfahren in Lp (En).
Uniform modular integrability and convergence properties for a class of Urysohn integral operators in function spaces
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We study smoothness spaces generated by maximal functions related to the local approximation errors of integral operators. It turns out that in certain cases these smoothness classes coincide with the spaces , 0 < p≤∞, introduced by DeVore and Sharpley [DS] by means of the so-called sharp maximal functions of Calderón and Scott. As an application we characterize the spaces in terms of the coefficients of wavelet decompositions.
Used of interpolatory linear positive operators for calculus the moments of the related probability distributions.
Аппроксимация некоторых интегралов, зависящих от двух параметров
Замечания о компактной аппроксимации в банаховых пространствах
Наилучшие методы приближения аналитических функций, заданных с погрешностью
О представлении произвольных функций некоторыми специальными рядами