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Equivariant shape theory

Published online by Cambridge University Press:  24 October 2008

Zvonko Čerin
Affiliation:
Department of Mathematics, University of Zagreb, Zagreb, Croatia. E-mail: zcerin@x400.srce.hr

Abstract

Equivariant shape theory is an improvement of equivariant homotopy theory which could be regarded as an equivariant version of Borsuk's shape theory. The main result in this paper is a description of the equivariant shape category ShG whose objects are equivariant spaces or G-spaces, i.e. topological spaces endowed with an action of a given topological group G, and whose morphisms are equivariant homotopy or G-homotopy classes of families of multi-valued functions which we call equivariant multi-nets or G-multi-nets. Previously equivariant shape theories have been described only under the assumptions that the group G is either finite or compact. We also study classes of G-spaces on which equivariant shape and equivariant homotopy coincide, look for conditions under which a G-map f: XY is an equivariant shape equivalence, and give some characterizations of G-spaces with trivial equivariant shape.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1995

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