Approximation with interpolatory constraints Academic Article uri icon


  • Given a triangular array of points on [ 1 , 1 ] [-1,1] satisfying certain minimal separation conditions, a classical theorem of Szabados asserts the existence of polynomial operators that provide interpolation at these points as well as a near-optimal degree of approximation for arbitrary continuous functions on the interval. This paper provides a simple, functional-analytic proof of this fact. This abstract technique also leads to similar results in general situations where an analogue of the classical Jackson-type theorem holds. In particular, it allows one to obtain simultaneous interpolation and a near-optimal degree of approximation by neural networks on a cube, radial-basis functions on a torus, and Gaussian networks on Euclidean space. These ideas are illustrated by a discussion of simultaneous approximation and interpolation by polynomials and also by zonal-function networks on the unit sphere in Euclidean space.

published proceedings


author list (cited authors)

  • Mhaskar, H. N., Narcowich, F. J., Sivakumar, N., & Ward, J. D.

citation count

  • 16

complete list of authors

  • Mhaskar, HN||Narcowich, FJ||Sivakumar, N||Ward, JD

publication date

  • May 2002