Article ID Journal Published Year Pages File Type
4655995 Journal of Combinatorial Theory, Series A 2010 7 Pages PDF
Abstract

For every k and r, we construct a finite family of axis-parallel rectangles in the plane such that no matter how we color them with k colors, there exists a point covered by precisely r members of the family, all of which have the same color. For r=2, this answers a question of S. Smorodinsky [S. Smorodinsky, On the chromatic number of some geometric hypergraphs, SIAM J. Discrete Math. 21 (2007) 676–687].

Related Topics
Physical Sciences and Engineering Mathematics Discrete Mathematics and Combinatorics