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A short proof of Greenbergs Theorem

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 Added by Gareth Jones
 Publication date 2019
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and research's language is English




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Greenberg proved that every countable group $A$ is isomorphic to the automorphism group of a Riemann surface, which can be taken to be compact if $A$ is finite. We give a short and explicit algebraic proof of this for finitely generated groups $A$.



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