Infinitesimal geometry of quasilinear mappings.
We consider the class of sense-preserving harmonic functions defined in the unit disk and normalized so that and , where and are analytic in the unit disk. In the first part of the article we present two classes and of functions from and show that if and , then the harmonic convolution is a univalent and close-to-convex harmonic function in the unit disk provided certain conditions for parameters and are satisfied. In the second part we study the harmonic sections (partial...