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Lifting homotopies through fixed points

Published online by Cambridge University Press:  14 November 2011

M. A. Armstrong
Affiliation:
Department of Mathematics, Science Laboratories, University of Durham, Durham

Synopsis

If G is a discontinuous group of homeomorphisms of a connected, locally path connected space X, which acts freely on X, then the projection π: XX/G is a covering map and has the homotopy lifting property. Here we allow the elements of G to have fixed points and use work of Rhodes to investigate how two loops in X are related if their projections are homotopic in X/G. This enables us to establish a formula for the fundamental group of the orbit space of a discontinuous group under very general conditions. Finally we show by means of an example that some restriction on the action near fixed points is needed for the formula to be valid.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1982

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References

1Armstrong, M. A. On the fundamental group of an orbit space. Proc. Cambridge Philos. Soc. 61 (1965), 639646.CrossRefGoogle Scholar
2Armstrong, M. A.. The fundamental group of the orbit space of a discontinuous group. Proc. Cambridge Philos. Soc. 64 (1968), 299301.CrossRefGoogle Scholar
3Armstrong, M. A.. Calculating the fundamental group of an orbit space. Proc. Amer. Math. Soc. 84 (1982), 267271.CrossRefGoogle Scholar
4Best, L. A.. On torsion free discrete subgroups of PSL (2, C) with compact orbit space. Canad. J. Math. 23 (1971), 451460.CrossRefGoogle Scholar
5Bredon, G. E.. Introduction to compact transformation groups. (New York: Academic Press, 1972).Google Scholar
6Donnelly, H. and Schultz, R.. Compact group actions and maps into aspherical manifolds, to appear.Google Scholar
7Griffiths, H. B.. Infinite products of semi-groups and local connectivity, Proc. London Math. Soc. 6 (1956), 455480.CrossRefGoogle Scholar
8Higgins, P. J. and Taylor, J.. The fundamental groupoid and the homotopy crossed complex of an orbit space. Proc. 1981 Conf. on Category Theory. Lecture Notes in Mathematics, to appear.CrossRefGoogle Scholar
9Maclachlan, C.. Modulus space is simply connected. Proc. Amer. Math. Soc. 29 (1971), 8586.CrossRefGoogle Scholar
10Rhodes, F.. On the fundamental group of a transformation group. Proc. London Math. Soc. 16 (1966). 635650.CrossRefGoogle Scholar