Recent Progress in Multivariate Approximation: 4th International Conference, Witten-Bommerholz(Germany), September 2000

These proceedings contain the main topics and results presented at the Fourth International Conference on Multivariate Approximation. The meeting took place during the week of September 24-29, 2000 at the now well-known "Haus Bommerholz", the guest-house of the University of Dortmund. It hosted 43 participants from 16 countries, and the program included 9 invited one-hour lectures, 21 contributed talks, and two problem sessions. The articles collected here are carefully peer-refereed and suitably edited for publication. Following the tradition of this series of conferences, the meeting was aimed at advancing selected topics of Multivariate Approximation Theory. These include approximation on compact sets (such as spheres, balls, or compact ho­ mogeneous manifolds), spherical designs and energy functionals, interpolation by radial basis functions and by splines, frame theory and Gabor analysis, re­ finable function systems and subdivision, properties of harmonic, polyharmonic and blending functions, sampling and data compression, among others. The editors would like to express their thanks to all who have given their sup­ port to the conference, and to the preparation of this book. In particular, our thanks go to the Deutsche Forschungsgemeinschaft for their funding of the con­ ference, to the University of Dortmund, and to the staff of Haus Bommerholz for their help running the conference, and to the Universities of Dortmund and Duisburg for the financial support of this proceedings volume.

Table of Contents:
Jochen W. Schmidt in Memoriam.- Best Approximation of Polynomials on the Sphere and on the Ball.- The Sign of a Harmonic Function Near a Zero.- Radial Basis Functions for the Sphere.- Cubature Formulae for Polyharmonic Functions.- On the Structure of Kergin Interpolation for Points in General Position.- Frames Containing a Riesz Basis and Approximation of the Inverse Frame Operator.- Kronecker Type Convolution of Function Vectors with one Refinable Factor.- Best One—Sided L1—Approximation by B2,1—Blending Functions.- Open Problem: Existence of Hermite Interpolatory Subdivision Schemes with Arbitrary Large Smoothnesses.- Asymptotic Formulas in Cardinal Interpolation and Orthogonal Projection.- Note on d—Extremal Configurations for the Sphere in ?d+1.- Some Cubature Formulae Using Mixed Type Data.- On an Extremal Problem Originating in Questions of Unconditional Convergence.- Node Insertion and Node Deletion for Radial Basis Functions.- Tangent Space Methods for Approximation on Compact Homogeneous Manifolds.- Open Problem Concerning Fourier Transforms of Radial Functions in Euclidean Space and on Spheres.- Local Lagrange Interpolation on Powell—Sabin Triangulations and Terrain Modelling.- The Geometry of Nodes in a Positive Quadrature on the Sphere.- Normalized Tight Frames in Finite Dimensions.- Publications of Jochen W. Schmidt.