A Riemannian symmetric space is a connected Riemannian manifold
such that for every point
there is an isometry
fixing
whose differential at
is
, where
is the identity operator
on the tangent space at
. Equivalently,
reverses every geodesic through
.
The Euclidean space, sphere, and hyperbolic space are symmetric spaces. More
generally, a Riemannian symmetric space can be represented as a homogeneous
space ,
where
is a Lie group of isometries
and
is the stabilizer of a point.
For example,
Symmetric spaces are basic objects in differential geometry and in the study of representations of Lie groups. Harmonic maps into such spaces can be studied using loop groups and the DPW method.