Yp. Liu et Gz. Lu, Simultaneous approximations for functions in Sobolev spaces by derivativesof polyharmonic cardinal splines, J APPROX TH, 101(1), 1999, pp. 49-62
We prove in this paper that functions in Sobolev spaces and their derivativ
es can be approximated by polyharmonic splines and their derivatives in L-p
(R-n) norms. Of particular interest are the remainder formulas of such appr
oximations and the order of convergence by the derivatives of cardinal poly
harmonic interpolational splines. (C) 1999 Academic Press.