Continuity of the barycentric extension of circle diffeomorphisms of H\"older continuous derivatives

Abstract

The barycentric extension due to Douady and Earle gives a conformally natural extension of a quasisymmetric automorphism of the circle to a quasiconformal automorphism of the unit disk. We consider such extensions for circle diffeomorphisms of H\"older continuous derivatives and show that this operation is continuous with respect to an appropriate topology for the space of the corresponding Beltrami coefficients.