A principal bundle with a Lie group consists of a manifold and a free proper smooth -action . There is a unique smooth manifold structure on the quotient space such that the canonical map is smooth. is called a base manifold and stands for the bundle. The most fundamental examples of principal bundles are the homogeneous spaces , where is a closed subgroup of . The pair is a Klein pair. A model geometry consists of a Klein pair and a Lie group with Lie algebra . In this paper, the author describes a Klein geometry as a principal bundle equipped with a -valued 1-form on having the properties (i) is an isomorphism on each fibre, (ii) for all , (iii) for each , (iv)
@article{701688, title = {An introduction to Cartan Geometries}, booktitle = {Proceedings of the 21st Winter School "Geometry and Physics"}, series = {GDML\_Books}, publisher = {Circolo Matematico di Palermo}, address = {Palermo}, year = {2002}, pages = {[61]-75}, mrnumber = {MR1972425}, zbl = {1028.53026}, url = {http://dml.mathdoc.fr/item/701688} }
Sharpe, Richard. An introduction to Cartan Geometries, dans Proceedings of the 21st Winter School "Geometry and Physics", GDML_Books, (2002), pp. [61]-75. http://gdmltest.u-ga.fr/item/701688/