A gap series with growth conditions and its applications.
Let denote the set of functions holomorphic in the unit disc, normalized clasically: , whereas is an arbitrarily fixed subset. In this paper various properties of the classes , of functions of the form are studied, where , , and denotes the Hadamard product of the functions and . Some special cases of the set were considered by other authors (see, for example, [15],[6],[3]).
We construct a nonbasic harmonic mapping of the unit disk onto a convex wedge. This mapping satisfies the partial differential equation where a(z) is a nontrivial extreme point of the unit ball of .
We prove that each degree two quasiregular polynomial is conjugate to Q(z) = z² - (p+q)|z|² + pqz̅² + c, |p| < 1, |q| < 1. We also show that the complexification of Q can be extended to a polynomial endomorphism of ℂℙ² which acts as a Blaschke product (z-p)/(1-p̅z) · (z-q)/(1-q̅z) on ℂℙ²∖ℂ². Using this fact we study the dynamics of Q under iteration.
We give a simple algebraic condition on the leading homogeneous term of a polynomial mapping from ℝ² into ℝ² which is equivalent to the fact that the complexification of this mapping can be extended to a polynomial endomorphism of ℂℙ². We also prove that this extension acts on ℂℙ²∖ℂ² as a quotient of finite Blaschke products.