In: Math
using these axioms ( finite affine plane ) :
AA1 : there exists at least 4 distinct points , no there of which are collinear .
AA2 : there exists at least one line with n (n>1) points on it .
AA3 : Given two distinct points , there is exactly one line incident with both of them .
AA4 : Given a line l and a point p not on l , there is exactly one line through p that does not intersect l .
prove : in an affine plane of order n , each line contains exactly n points .