The Third International Conference on Multivariate Approximation at
``Haus Bommerholz'', the guest-house of the University of Dortmund,
took place during the week of September 27 through October 2, 1998.
It was attended by 50 participants from 18 countries. The program
included 10 invited lectures, 25 contributed talks, and two problem
sessions. In these Proceedings we collect most of the lectures,
suitably prepared by the authors for publication, and carefully
peer-refereed.
As was the case for the preceding conferences, the meeting was
intended to advance several selected topics from modern aspects of
Multivariate
Approximation Theory. This time, emphasis was put on the
following subjects: Interpolation and Approximation on Spheres and
Balls, Approximation by Solutions of Partial Differential
Equations, Construction of Node Systems, and Scattered Data
Techniques. Leading experts in these areas and quite a number of
young researchers made the meeting a stimulating event, with lively
discussions and scientific interactions to support and initiate
future research.
The editors are grateful to all who have contributed to the
success of the conference and to the production of this
Proceedings volume. In particular, our thanks go to the Deutsche
Forschungsgemeinschaft whose funding made the conference possible,
and to the Ministerium für Schule, Weiterbildung,
Wissenschaft und Forschung of the
Land Nordrhein-Westfalen for sponsoring this volume. We
acknowledge the help of the authors and the referees to guarantee
publications of high scientific standard, and we thank the
WILEY-VCH publishers
for their kind cooperation.
In addition, we acknowledge the extensive help of Dr. Hermann Hoch
and Dipl.-Math. Jörg Zabold (Duisburg) during the production
of this Proceedings volume.
Finally, we would
especially like to thank the conference secretary, Mrs. Lamprecht, and
the staff of Haus Bommerholz, for all their help.
May 1, 1999
Werner Haußmann
Kurt Jetter
Manfred Reimer
Deutsche Forschungsgemeinschaft (DFG)
whose funding made the conference possible.
The production of this volume was sponsored by the
Ministerium für Schule und Weiterbildung,
Wissenschaft und Forschung
des Landes Nordrhein-Westfalen.
We are grateful for the generous support.
The Editors
Participants 9
Scientific Program of the Conference 15
Problems of Approximation Theory in Discrete Geometry N. N. Andreev and V. A. Yudin 19
Dense Vector Spaces of Universal Harmonic Functions D. H. Armitage 33
Best One-sided Subharmonic Functions D. H. Armitage and S. J. Gardiner 43
Numerical Stability of Fast Fourier TransformsG. Baszenski, R. Xuefang and M. Tasche 57
The Saturation Theorem for Box Spline Orthogonal ProjectionM. Beska and K. Dziedziul 73
Problem on Monotonic Behaviour of Bernstein OperatorsM. Beska and K. Dziedziul 84
Best One-Sided-Approximation by Blending Functions B. D. Bojanov, D. P. Dryanov,W. Haußmann and G. P. Nikolov 85
On the Asymptotics of Points which Maximize Determinants of the Form L. Bos and U. Maier 107
Besov Regularity for the Stokes Problem F.-J. Delvos 139
Multiscale Modelling from Geopotential DataW. Freeden, O. Glockner and R. Litzenberger 151
On a Family of Orthogonal Wavelets on the Quincunx Grid: Open Regularity QuestionsA. Gottscheber and G. Steidl 175
Average Case Analysis of Numerical Integration P. J. Grabner, P. Liardet and R. F. Tichy 185
Cubature Formulas on SpheresH. König 201
Numerical Calculation of Spherical DesignsU. Maier 213
On Bivariate Spline SpacesG. Nürnberger and F. Zeilfelder 227
Spherical Polynomial Approximations: A SurveyM. Reimer 231
Range Restricted Interpolation by Cubic-Splines on Clough-Tocher J. W. Schmidt 253
Some Error Estimates for Periodic Interpolation of Functions from Besov SpacesW. Sickel and F. Sprengel 269
The Uniform Error of Hyperinterpolation on the Sphere I. H. Sloan and R. S. Womersley 289
Simultaneous Approximation in the Dirichlet SpaceA. Stray 307
The Equivalence between Weighted Moduli of Smoothness on a Simplex and their ApplicationsP.-C. Xuan 321
Monday, September 28:
Opening Session: Chair K. Jetter
9:00 Opening of the Conference
9:30 - 10:30 R. F. Tichy: Point Distributions, Discrepancy and Applications
Morning Session: Chair R. F. Tichy
11:00 - 11:30 V. A. Yudin: Extremal Dispositions of Points on the Sphere and the Torus
11:30 - 12:00 J. J. Seidel: Spherical Designs
12:00 - 12:30 U. Maier: Numerical Calculation of Spherical Designs
Afternoon Session: Chair: A. Stray
16:00 - 17:00 F. Pérez-Gonzalez: Approximation in the L1-Norm by Element of a Uniform Algebra
17:00 - 17:30 S. J. Gardiner: Best One-Sided L1-Approximation by Harmonic and Subharmonic Functions
17:30 - 18:00 D. H. Armitage: Universal Harmonic Functions
Tuesday, September 29:
1st Morning Session: Chair: J. W. Schmidt
9:00 - 10:00 G. Plonka: A New Factorization of Mask Symbols of Scaling Vectors
2nd Morning Session: Chair: H. König
10:00 - 10:30 J. Prestin: Polynomial Wavelets
11:00 - 11:30 H. M. Möller: H-Bases: A Tool for Polynomial Interpolation and System Solving
11:30 - 12:30 L. Karp: Generalized Newtonian Potential and its Applications
Afternoon Session: Chair: J. D. Ward
16:00 - 17:00 W. Freeden: Inverse Multiscale Modelling of the Geopotential
17:00 - 17:30 V. Michel: A New Way of Reconstructing the Density of the Earth from Geodetic Measurements
17:30 - 18:00 J. W. Schmidt: Scattered Data Interpolation with Rational Splines on PS Refinements
Evening Session: Chair: G. Plonka
19:30 - 20:00 A. Faul: Proof of Convergence of an Iterative Technique for Thin Plate Splines in Two Dimensions
20:00 - 20:30 A. Le Méhauté : Inf-Convolution and Radial Basis Functions
20:30 - 21:00 F.-J. Delvos: Optimal Interpolation in Multivariate Periodic Hilbert Spaces
21:00 - 21:30 1st Problem Session
Wednesday, September 30:
1st Morning Session: Chair: S. Riemenschneider
9:00 - 10:00 W. Dahmen: Adaptive Wavelet Methods for Elliptic Problems - Convergence Rates
10:00 - 10:30 A. Kunoth: Multiscale Galerkin Methods for Elliptic PDEs - Appending Boundary Conditions by Lagrange Multipliers and Fictitious Domains
2nd Morning Session: Chair: D. Braess
11:00 - 11:30 S. Dahlke: Recent Results on Besov Regularity for Elliptic Boundary Value Problems
11:30 - 12:00 P.-C. Xuan: The Equivalence Between the Weighted K-Functional and Moduli of Smoothness on the Simplex and Their Applications
12:00 - 12:30 F. Sprengel: Interpolation on Sparse Grids and Nikol'ski-Besov Spaces of Dominating Mixed Smoothness
Thursday, October 1:
1st Morning Session: Chair: Z. Ciesielski
9:00 - 10:00 M. Reimer: Spherical Polynomial Approximation: A Survey
10:00 - 10:30 L. Bos: On the Asymptotics of Fekete Points for Radial Basis Functions
2nd Morning Session: Chair: L. Bos
11:00 - 11:30 S. de Marchi: On the Limit under Scaling of Polynomial Lagrange Interpolation on Spheres and Analytic Manifolds
11:30 - 12:30 A. Stray: Simultaneous Approximation in the Dirichlet Space
Afternoon Session: Chair: G. Nürnberger
16:00 - 17:00 H. König: Cubature Formulas on Spheres
17:00 - 17:30 M. Beska: The Saturation Problem for some Classical Operators
17:30 - 18:00 S. D. Riemenschneider: Cardinal Interpolation by Gaussian Radial Basis Functions: Behaviour as
Evening Session: Chair: M. Reimer
19:30 - 20:00 M. Tasche: How Stable are Fast Cosine Transforms?
20:00 - 21:00 2nd Problem Session
Friday, October 4:
1st Morning Session: Chair: I. H. Sloan
9:00 - 10:00 J. D. Ward: Approximation from Spaces of Shifts and of a Positive Definite Kernel
10:00 - 10:30 P. Binev: Using Three-Scale Equation in Adaptive Refinement
2nd Morning Session: Chair: W. Haußmann
11:00 - 11:30 O. Davydov: Bases of Bivariate Piecewise Polynomials
11:30 - 12:00 G. Nürnberger: Spline Interpolation on Triangulations
12:00 - 12:30 I. H. Sloan: Uniform Constructive Approximation by Polynomials on the Sphere
12:30 Closing of the Conference
You can contact the editors at the following email addresses:
Werner Haußmann Kurt Jetter Manfred Reimer