51XX 


Geometry {For algebraic geometry, see 14XX} 

51Axx 

Linear incidence geometry 


51A05 
General theory and projective geometries 


51A10 
Homomorphism, automorphism and dualities 


51A15 
Structures with parallelism 


51A20 
Configuration theorems 


51A25 
Algebraization [See also 12Kxx, 20N05] 


51A30 
Desarguesian and Pappian geometries 


51A35 
NonDesarguesian affine and projective planes 


51A40 
Translation planes and spreads 


51A45 
Incidence structures imbeddable into projective geometries 


51A50 
Polar geometry, symplectic spaces, orthogonal spaces 


51A99 
None of the above, but in this section 