You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
Two Extensions of the Sard-Schoenberg Theory of Best Approximation
SIAM Journal on Numerical Analysis
Vol. 11, No. 1 (Mar., 1974), pp. 45-51
Published by: Society for Industrial and Applied Mathematics
Stable URL: http://www.jstor.org/stable/2156429
Page Count: 7
Preview not available
A linear functional J(f) defined on Cm - 1 [ a, b ] can be approximated by appropriate linear combinations of function values f(xi) at discrete points x1, ⋯, xn ∈ [ a, b ]. The problem of best approximation with respect to a given class of functions was posed by Sard  and solved for special classes by Schoenberg . We give a simplified proof of Schoenberg's result which immediately carries over to the periodic case. An example for its application is the attenuation factors in practical Fourier analysis. Another extension is possible if interpolation is replaced by smoothing.
SIAM Journal on Numerical Analysis © 1974 Society for Industrial and Applied Mathematics