The Boundary Schwarz lemma for harmonic and pluriharmonic mappings and some generalisations (2111.02384v5)

Abstract: The main purpose of this paper is to develop some methods to investigate the Schwarz type lemmas of holomorphic mappings and pluriharmonic mappings in Hilbert and Banach spaces. Initially, we extend the classical Schwarz lemmas of holomorphic mappings to Hilbert and Banach spaces. Furthermore, we improve and generalize the classical Schwarz lemmas of planar harmonic mappings into the sharp forms of Banach spaces, and present some applications to sharp boundary Schwarz type lemmas for pluriharmonic mappings in Hilbert and Banach spaces and the obtained results provide the improvements and generalizations of some latest corresponding results in this subject. In the last section we studied harmonic and hyperbolical-harmonic function mapping unit ball in Euclidial n-space, to unit ball in Euclidial m-space, taking prescribed value in the origin, which improved some previous results.