Applications of a theorem of Singerman about Fuchsian groups

Hugo Parlier
2008
Article

Résumé

Assume that we have a (compact) Riemann surface S, of genus greater than 2, with S = D/Gamma, where D is the complex unit disc and Gamma is a surface Fuchsian group. Let us further consider that S has an automorphism group G in such a way that the orbifold S/G is isomorphic to D/Gamma' where Gamma' is a Fuchsian group such that Gamma (sic) Gamma' and Gamma' has signature sigma appearing in the list of non-finitely maximal signatures of Fuchsian groups of Theorems 1 and 2 in [6]. We establish an algebraic condition for G such that if G satisfies such a condition then the group of automorphisms of S is strictly greater than G, i.e., the surface S is more symmetric that we are supposing. In these cases, we establish analytic information on S from topological and algebraic conditions.

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