  A proposal is made for what could well be the most natural symmetrical
Riemannian spaces which are homogeneous but not isotropic, i.e. of what could
well be the most natural class of symmetrical spaces beyond the spaces of
constant Riemannian curvature, that is, beyond the spaces which are homogeneous
and isotropic, or, still, the spaces which satisfy the axiom of free mobility.
