Local error estimates for radial basis function interpolation of scattered data

Introducing a suitable variational formulation for the local error of scattered data interpolation by radial basis functions φ(r), the error can be bounded by a term depending on the Fourier transform of the interpolated function f and a certain ‘Kriging function’, which allows a formulation as an integral involving the Fourier transform of φ. The explicit construction of locally well-behaving admissible coefficient vectors makes the Kriging function bounded by some power of the local density h of data points. This leads to error estimates for interpolation of functions f whose Fourier transform f is ‘dominated’ by the nonnegative Fourier transform ψˆ of ψ(x) = ψ(∥x∥) in the sense ∫|fˆ|2ψˆ-1dt 1, s ∉ 2N, and φ(r) = rs log r for s ε 2N, which are shown to have accuracy O(hs/2)