We find sufficient conditions for a cotriad of which the objects are locally trivial fibrations, in order that the push-out be a locally trivial fibration. As an application, the universal $G$-bundle of a finite group $G$, and the classifying space is modeled by locally finite spaces. In particular, if $G$ is finite, then the universal $G$-bundle is the limit of an ascending chain of finite spaces. The bundle projection is a covering projection.
@article{118973, author = {Peter Witbooi}, title = {Finite spaces and the universal bundle of a group}, journal = {Commentationes Mathematicae Universitatis Carolinae}, volume = {38}, year = {1997}, pages = {791-799}, zbl = {0938.55024}, mrnumber = {1603722}, language = {en}, url = {http://dml.mathdoc.fr/item/118973} }
Witbooi, Peter. Finite spaces and the universal bundle of a group. Commentationes Mathematicae Universitatis Carolinae, Tome 38 (1997) pp. 791-799. http://gdmltest.u-ga.fr/item/118973/
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