An extremal problem for harmonic self-mappings of the unit disk

摘要

Let Aut(H)(D) be the class of harmonic automorphisms of the unit disk D. For f(re(i phi)) = Sigma(infinity)(n=-infinity) c(n)r(vertical bar n vertical bar)e(in phi) is an element of Aut(H)(D) the upper bounds of Re Sigma(n)(k=1){c(k) + c(-k)} are given. (c) 2006 Elsevier Inc. All rights reserved.