N-point Padé approximants and two-sided estimates of errors on the real axis for Stieltjes functions

Upper and lower estimates of Stieltjes function by N-point Padé approximants can be obtained using the new general inequality reported by Tokarzewski et al. (Arch. Mech. 54 (2002) 141-153) and rigorously proved in the present paper. In addition, we prove that the multipoint Padé approximants to Stieltjes function are symmetric with respect to the order of choice of the considered points.