Appendix D. Exceptional Orbits of Highest Dimension
Appendix D recalls notions and results from the theory of Lie groups (exceptional orbits of Lie groups acting on smooth manifolds) and the theory of cohomogeneity one Riemannian manifolds.
Keywords: Action; orbit; isotropy group; foliated action; locally free action; singular orbit; principal orbit; exceptional orbit; cohomogeneity one (Riemannian manifold); normal geodesic; principal curvature.
A smooth
action of a Lie group
G on a
n-dimensional
C∞ manifold
M is a
C∞ map

such that

and
for any ...