Interpolation Mixed with I2-Approximation Original Research Article

We consider sqn roots of unity and define a class RσN*(Us, f) of rational functions which interpolate a given analytic function f on Us, a large subset of the roots of unity satisfying a congruence relation. f is then approximated over RσN*(f, Us) with respect to l(2)-norm on the complement of Us. We also discuss Walsh type equi convergence.