Collinearity-preserving functions between Desarguesian planes
Collinearity-preserving functions between Desarguesian planes
Using concepts from valuation theory, we obtain a characterization of all collinearity-preserving functions from one affine or projective Desarguesian plane into another. The case in which the planes are projective and the range contains a quadrangle has been treated previously in the literature. Our results permit one or both planes …