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Generalizations of the Crossing Lemma

Combinatorics 2025-09-18 v1

Abstract

The crossing number of a graph is the minimum number of crossings over all of its drawings on the plane. The Crossing Lemma, proved more than 40 years ago, is a tight lower bound on the crossing number of a graph in terms of the number of vertices and edges. It is definitely the most important inequality on crossing numbers. We review some generalizations and applications of the Crossing Lemma.

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Cite

@article{arxiv.2509.14074,
  title  = {Generalizations of the Crossing Lemma},
  author = {Geza Toth},
  journal= {arXiv preprint arXiv:2509.14074},
  year   = {2025}
}

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27 pages