Barany, Imre; Larman, D.G. - Cowles Foundation for Research in Economics, Yale University - 1990
The main result of this paper is that given n red, n white, and n green points in the plane, it is possible to form n vertex-disjoint triangles Delta_{1},...,Delta_{n} in such a way that the Delta_{i} has one red, one white, and one green vertex for every i = 1,...,n and the intersection of...