51E24 Buildings and the geometry of diagrams

51E30 Other finite incidence structures [See also <a href="#code:05B30">05B30</a>]

51E99 None of the above, but in this section

51F15 Reflection groups, reflection geometries [See also <a href="#code:20H10">20H10</a>, <a href="#code:20H15">20H15</a>; for Coxeter groups, see <a href="#code:20F55">20F55</a>]

51F20 Congruence and orthogonality [See also <a href="#code:20H05">20H05</a>]

51F25 Orthogonal and unitary groups [See also <a href="#code:20H05">20H05</a>]

51F99 None of the above, but in this section

51Gxx Ordered geometries (ordered incidence structures, etc.)

51G05 Ordered geometries (ordered incidence structures, etc.)

51G99 None of the above, but in this section

51H10 Topological linear incidence structures

51H15 Topological nonlinear incidence structures

51H20 Topological geometries on manifolds [See also <a href="#code:57-XX">57-XX</a>]

51H25 Geometries with differentiable structure [See also <a href="#code:53Cxx">53Cxx</a>, <a href="#code:53C70">53C70</a>]

51H30 Geometries with algebraic manifold structure [See also <a href="#code:14-XX">14-XX</a>]

51H99 None of the above, but in this section

51J20 Representation by near-fields and near-algebras [See also <a href="#code:12K05">12K05</a>, <a href="#code:16Y30">16Y30</a>]

51J99 None of the above, but in this section

51K99 None of the above, but in this section

51Lxx Geometric order structures [See also <a href="#code:53C75">53C75</a>]

51L05 Geometry of orders of nondifferentiable curves

51L15 $n$-vertex theorems via direct methods

51L99 None of the above, but in this section

51M04 Elementary problems in Euclidean geometries

51M05 Euclidean geometries (general) and generalizations

51M09 Elementary problems in hyperbolic and elliptic geometries

51M10 Hyperbolic and elliptic geometries (general) and generalizations

51M16 Inequalities and extremum problems {For convex problems, see <a href="#code:52A40">52A40</a>}

51M20 Polyhedra and polytopes; regular figures, division of spaces [See also <a href="#code:51F15">51F15</a>]