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Additive Automorphic Functions and Bloch Functions

Published online by Cambridge University Press:  20 November 2018

Rauno Aulaskari
Affiliation:
Department of Mathematics University of Joensuu SF-80101 Joensuu 10 Finland
Peter Lappan
Affiliation:
Department of Mathematics Michigan State University East Lansing, Michigan 48824 U.S.A.
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Abstract

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A function f analytic in the unit disk D is said to be strongly uniformly continuous hyperbolically, or SUCH, on a set E ⊂ D if for each > 0 there exists a δ > 0 such that |f(z) — f(z')| < ∊ whenever z and z' are points in E and the hyperbolic distance between z and z' is less than δ. We show that f is a Bloch function in D if and only if |f| is SUCH in D. A function f is said to be additive automorphic in D relative to a Fuchsian group F if, for each γ ∊ Γ, there exists a constant Aγ such that f(γ(z)) =f(z) + Aγ. We show that if an analytic function f is additive automorphic in D relative to a Fuchsian group Γ, where Γ is either finitely generated or if the fundamental region F of Γ has the right kind of structure, and if |f| is SUCH in F, then f is a Bloch function. We show by example that some restrictions on Γ are needed.

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1994

References

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