On the Univalence and Quasiconformal Extensions Criterion for Harmonic Mappings Associated with Pre-Schwarzian Derivative
摘要
As a generalization of Ahlfors’s results for analytic functions, by using the pre-Schwarzian derivative of harmonic mappings, the authors obtain a criterion of univalence and quasiconformal extension for harmonic functions. As applications, they give a lower bound of the inner radius of univalency by means of pre-Schwarzian derivative of harmonic mappings for a planar domain.