Criteria for membership of the Besov spaces BS pq.
Cubature Formulae which are Exact on Spaces P, Intermediate Between Pk and Qk.
Cubic splines with minimal norm
Natural cubic interpolatory splines are known to have a minimal -norm of its second derivative on the (or class of interpolants. We consider cubic splines which minimize some other norms (or functionals) on the class of interpolatory cubic splines only. The cases of classical cubic splines with defect one (interpolation of function values) and of Hermite splines (interpolation of function values and first derivatives) with spline knots different from the points of interpolation are discussed....
Curriculum vita of Prof. Vasil Atanasov Popov
Our primary goal in this preamble is to highlight the best of Vasil Popov’s mathematical achievements and ideas. V. Popov showed his extraordinary talent for mathematics in his early papers in the (typically Bulgarian) area of approximation in the Hausdorff metric. His results in this area are very well presented in the monograph of his advisor Bl. Sendov, “Hausdorff Approximation”.
Darstellungen von Liegruppen und Approximationsprozesse auf Banachräumen.
Das asymptotische Verhalten der Peanokerne einiger interpolatorischer Quadraturverfahren.
Das Saturationsverhalten spezieller Summationsverfahren auf kompakten Gruppen.
Data approximation using polyharmonic radial basis functions
The paper is concerned with the approximation and interpolation employing polyharmonic splines in multivariate problems. The properties of approximants and interpolants based on these radial basis functions are shown. The methods of such data fitting are applied in practice to treat the problems of, e.g., geographic information systems, signal processing, etc. A simple 1D computational example is presented.
Data compression with -approximations based on splines
The paper contains short description of -algorithm for the approximation of the function with two independent variables by the sum of products of one-dimensional functions. Some realizations of this algorithm based on the continuous and discrete splines are presented here. Few examples concerning with compression in the solving of approximation problems and colour image processing are described and discussed.
DCR2: An Improved Algorithm for l¶ Rational Approximation on Intervals.
De nouveaux espaces de Banach sans la propriété d'approximation
Degenerate evolution problems and Beta-type operators
The present paper is concerned with the study of the differential operator Au(x):=α(x)u”(x)+β(x)u’(x) in the space C([0,1)] and of its adjoint Bv(x):=((αv)’(x)-β(x)v(x))’ in the space , where α(x):=x(1-x)/2 (0≤x≤1). A careful analysis of their main properties is carried out in view of some generation results available in [6, 12, 20] and [25]. In addition, we introduce and study two different kinds of Beta-type operators as a generalization of similar operators defined in [18]. Among the corresponding...
Degree of Best Approximation by Trigonometric Blending Functions.
Degree Of Convergence Of Quasi-Hermite-Fejér Interpolation
Denseness of the spaces of Lizorkin type in the mixed -spaces
Density in approximation theory.
Density in the space of topological measures
Topological measures (formerly "quasi-measures") are set functions that generalize measures and correspond to certain non-linear functionals on the space of continuous functions. The goal of this paper is to consider relationships between various families of topological measures on a given space. In particular, we prove density theorems involving classes of simple, representable, extreme topological measures and measures, hence giving a way of approximating various topological measures by members...
Density methods and results in approximation theory
Approximation theory and functional analysis share many common problems and points of contact. One of the areas of mutual interest is that of density results. In this paper we briefly survey various methods and results in this area starting from work of Weierstrass and Riesz, and extending to more recent times.
Density of Polynomials in the L^2 Space on the Real and the Imaginary Axes and in a Sobolev Space
2000 Mathematics Subject Classification: 41A10, 30E10, 41A65.In this paper we consider an L^2 type space of scalar functions L^2 M, A (R u iR) which can be, in particular, the usual L^2 space of scalar functions on R u iR. We find conditions for density of polynomials in this space using a connection with the L^2 space of square-integrable matrix-valued functions on R with respect to a non-negative Hermitian matrix measure. The completness of L^2 M, A (R u iR ) is also established.
Density theorems for sampling and interpolation in the Bargmann-Fock space II.