51H05 General theory
51H10 Topological linear incidence structures
51H15 Topological nonlinear incidence structures
51H20 Topological geometries on manifolds [See also 57-XX]
51H25 Geometries with differentiable structure [See also 53Cxx, 53C70]
51H30 Geometries with algebraic manifold structure [See also 14-XX]
51H99 None of the above, but in this section