51Dxx Geometric closure systems

• 51D05 Abstract (Maeda) geometries
• 51D10 Abstract geometries with exchange axiom
• 51D15 Abstract geometries with parallelism
• 51D20 Combinatorial geometries [See also 05B25, 05B35]
• 51D25 Lattices of subspaces [See also 05B35]
• 51D30 Continuous geometries and related topics [See also 06Cxx]
• 51D99 None of the above, but in this section