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Simplifying group actions
The equivariant blow-up construction can simplify the orbit structure of a G-manifold. For abelian G the action can be simplified to an action in which all isotropy subgroups are Z 2-vector spaces and the codimension of the set of points having any isotropy subgroup is just the dimension of that sub...
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Published in: | Topology and its applications 1997, Vol.75 (1), p.13-31 |
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Main Author: | |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The equivariant blow-up construction can simplify the orbit structure of a
G-manifold. For abelian
G the action can be simplified to an action in which all isotropy subgroups are
Z
2-vector spaces and the codimension of the set of points having any isotropy subgroup is just the dimension of that subgroup as a
Z
2-vector space. Such actions are called nonsingular. Nonsingular actions have smooth quotient spaces (with corners). Moreover, the tangent bundle of a nonsingular action of an abelian group
G on
M can be written as a direct sum of the tangent bundle of the quotient manifold plus a sum of line bundles which are the extensions (to the whole of
M) of the normal bundles of the various fixed point sets. |
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ISSN: | 0166-8641 1879-3207 |
DOI: | 10.1016/S0166-8641(96)00084-3 |