Tschebyshev-Pad\'e approximations for multivalued functions

Abstract

We discuss the relation between the linear Tschebyshev-Pad\'e approximations to analytic function $f$ and the diagonal type I Hermite-Pad\'e polynomials for the tuple of functions $[1,f_1,f_2]$ where the pair of functions $f_1,f_2$ forms certain Nikishin system. An approach is proposed of how to extend the seminal Stahl's Theory for Pad\'e approximations for multivalued analytic functions to the Tschebyshev-Pad\'e approximations. The approach is based on the relation between Tschebyshev-Pad\'e approximations and Hermite-Pad\'e polynomials and also on a connection of Hermite-Pad\'e polynomials and multipoint Pad\'e approximants.