Schottky Uniformizations of Z22 Actions on Riemann Surfaces

Given a closed Riemann surface S together a group of its conformal automorphisms H _= Z22 , it is known that there are Schottky uniformizations of S realizing H. In this note we proceed to give an explicit Schottky uniformizations for each of all different topological actions of Z22 as group of conformal automorphisms on a closed Riemann surface.Given a closed Riemann surface S together a group of its conformal automor phisms H Z2 , it is known that there are Schottky uniformizations of S real =2 izing H . In this note we proceed to give an explicit Schottky uniformizations for each of all different topological actions of Z2 as group of conformal automor 2 phisms on a closed Riemann surface

REGULAR FOURFOLD COVERINGS WITH RESPECT TO THE IDENTITY AUTOMORPHISM

The aim of this paper is to count the isomorphism classes of regular fourfold coverings of a graph with respect to the identity automorphism, as M. Hofmeister did for double coverings. (C) 1993 John Wiley & Sons, Inc.X115sciescopu