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Polychromatic Colorings of Unions of Geometric Hypergraphs

Combinatorics 2021-12-07 v1 Computational Geometry Discrete Mathematics

Abstract

We consider the polychromatic coloring problems for unions of two or more geometric hypergraphs on the same vertex sets of points in the plane. We show, inter alia, that the union of bottomless rectangles and horizontal strips does in general not allow for polychromatic colorings. This strengthens the corresponding result of Chen, Pach, Szegedy, and Tardos [Random Struct. Algorithms, 34:11-23, 2009] for axis-aligned rectangles, and gives the first explicit (not randomized) construction of non-22-colorable hypergraphs defined by axis-parallel rectangles of arbitrarily large uniformity.

Keywords

Cite

@article{arxiv.2112.02894,
  title  = {Polychromatic Colorings of Unions of Geometric Hypergraphs},
  author = {Vera Chekan and Torsten Ueckerdt},
  journal= {arXiv preprint arXiv:2112.02894},
  year   = {2021}
}