Limit cycles bifurcating from isochronous surfaces of revolution in

In this paper we study the number of limit cycles bifurcating from isochronous surfaces of revolution contained in R 3 , when we consider polynomial perturbations of arbitrary degree. The method for studying these limit cycles is based on the averaging theory and on the properties of Chebyshev systems. We present a new result on averaging theory and generalizations of some classical Chebyshev systems which allow us to obtain the main results.