A Cartan geometry of the General Linear symmetry is formulated by dividing
out the displacements from the group. The resulting action is quadratic in
curvature, polynomial in all the (minimal) variables, and describes an observer
space that, in the symmetry-broken phase, reproduces the predictions of General
Relativity in the presence of dark matter.Comment: 6 pages, no figures. Contribution to the proceedings of the
conference "Teleparallel Universes in Salamanca
