Title: Algebraic criteria to decide if a finite group acts effectively on a model aspherical manifold
Authors: Malfait, Wim # ×
Issue Date: Aug-1998
Publisher: Academic press inc
Series Title: Journal of algebra vol:206 issue:1 pages:51-66
Abstract: For an aspherical manifold M, arising from a Seifert fiber space construction, it is known that, under some additional conditions on M, a finite abstract kernel psi: F --> Out(pi 1(M)) can be (effectively) geometrically realized by a group of fiber preserving homeomorphisms of M if and only if psi can be realized by an (admissible) group extension 1 --> pi(1)(M) --> E --> F --> 1. Hence, the study of the symmetry of such a manifold (in terms of finite effective actions on M) can be converted into a group-theoretical study of realizing (algebraically) finite abstract kernels F --> Out(pi(1)(M)). This question, conceptually, is well understood: there exists an extension realizing a given abstract kernel if and only if the corresponding third cohomology class, called the obstruction, vanishes. Unfortunately, a straightforward computation of this obstruction can be extremely hard. In this paper, we present some criteria which solve this problem for certain finite abstract kernels. Instead of using cohomological arguments, a completely different, rather technical and computational approach, based on the Reidemeister-Schreier method for presenting subgroups of finite index in a given finitely presented group, is followed. Not only the actual results but also this approach is of interest since it certainly allows one to produce similar criteria for other finite groups. (C) 1998 Academic Press.
ISSN: 0021-8693
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Mathematics, Campus Kulak Kortrijk
× corresponding author
# (joint) last author

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