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A Note on Regular Coverings of Closed Orientable Surfaces
Published online by Cambridge University Press: 18 May 2009
Extract
The object of this note is to study the regular coverings of the closed orientable surface of genus 2.
Let the closed orientable surface Fh of genus h be a covering of F2 and let and f be the fundamental groups respectively. Then is a subgroup of f of index n = h − 1. A covering is called regular if is normal in f.
Conversely, let be a normal subgroup of f of finite index. Then there is a uniquely determined regular covering Fh such that is the fundamental group of Fh. The covering Fh is an orientable surface. Since the index n of in f is supposed to be finite, Fh is closed, and its genus is given by n = h − 1.
The fundamental group f can be defined by
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- Copyright © Glasgow Mathematical Journal Trust 1961
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