On Markov's theorem for multi-level Hermite–Padé approximants of a Nikishin system

We consider a mixed type Hermite–Padé approximation problem of a Nikishin system of functions in which the generating measures may have unbounded or touching supports and give a Markov type theorem on the convergence of the approximating rational functions.
This is a joint work with Luis Giraldo Gonzalez Ricardo and Sergio Medina Peralta.