51XX 


Geometry {For algebraic geometry, see 14XX} 

51Hxx 

Topological geometry 


51H05 
General theory 


51H10 
Topological linear incidence structures 


51H15 
Topological nonlinear incidence structures 


51H20 
Topological geometries on manifolds [See also 57XX] 


51H25 
Geometries with differentiable structure [See also 53Cxx, 53C70] 


51H30 
Geometries with algebraic manifold structure [See also 14XX] 


51H99 
None of the above, but in this section 