Chromatic properties of generic planar configurations of points
Résumé
We study the Orchard relation for generic configurations of points in the plane (also called order types). We introduce infinitesimally-close points and analyse the relation of this notion with the Orchard relation. The second part of the paper deals with monochromatic configurations (for the Orchard relation). We give the complete list of all monochromatic configurations up to 7 points and present some constructions and families of monochromatic configurations.