HIGHER ORDER HERMITE-FEJÉR INTERPOLATION ON THE UNIT CIRCLE.

The aim of this paper is to study the approximation of functions using a higher-order Hermite-Fej´er interpolation process on the unit circle. The system of nodes is composed of vertically projected zeros of Jacobi polynomials onto the unit circle with boundary points at ±1. Values of the polynomial and its first four derivatives are fixed by the interpolation conditions at the nodes. Convergence of the process is obtained for analytic functions on a suitable domain, and the rate of convergence is estimated. [ABSTRACT FROM AUTHOR]