51XX 


Geometry {For algebraic geometry, see 14XX} 

51Lxx 

Geometric order structures [See also 53C75] 


51L05 
Geometry of orders of nondifferentiable curves 


51L10 
Directly differentiable curves 


51L15 
$n$vertex theorems via direct methods 


51L20 
Geometry of orders of surfaces 


51L99 
None of the above, but in this section 