G-Actions on Riemann Surfaces and the associated Group of Singular Orbit Data

dc.creatorGrieder, Ralph
dc.date1999-02-06
dc.date.accessioned2026-07-07T05:27:50Z
dc.date.available2026-07-07T05:27:50Z
dc.descriptionLet $G$ be a finite group. To every smooth $G$-action on a compact, connected and oriented Riemann surface we can associate its data of singular orbits. The set of such data becomes an Abelian group $B_G$ under the $G$-equivariant connected sum. The map which sends $G$ to $B_G$ is functorial and carries many features of the representation theory of finite groups. In this paper we will give a complete computation of the group $B_G$ for any finite group $G$. There is a surjection from the $G$-equivariant cobordism group of surface diffeomorphisms $Ω_G$ to $B_G$. We will prove that the kernel of this surjection is isomorphic to $H_2(G;Z)$. Thus $Ω_G$ is an Abelian group extension of $B_G$ by $H_2(G;Z)$. Finally we will prove that the group $B_G$ contains only elements of order two if and only if every complex character of $G$ has values in $R$. This property shows a strong relationship between the functor $B$ and the representation theory of finite groups.
dc.description23 pages. See also http://www.math.nwu.edu/~ralph/
dc.identifierhttps://arxiv.org/abs/math/9902048
dc.identifierhttp://arxiv.org/abs/math/9902048
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/78071
dc.subjectAlgebraic Topology
dc.subjectGroup Theory
dc.subject57M60; 57R85; 20C15 (Primary) 58G10 (Secondary)
dc.titleG-Actions on Riemann Surfaces and the associated Group of Singular Orbit Data
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