In this paper we study the hypergraph Zarankiewicz’s problem in a geometric setting - for r-partite intersection hypergraphs of families of geometric objects. Our main results are essentially sharp bounds for families of axis-parallel boxes in ℝ^d and families of pseudo-discs. For axis-parallel boxes, we obtain the sharp bound O_{d,t}(n^{r-1}((log n)/(log log n))^{d-1}). The best previous bound was larger by a factor of about (log n)^{d(2^{r-1}-2)}. For pseudo-discs, we obtain the bound O_t(n^{r-1}(log n)^{r-2}), which is sharp up to logarithmic factors. As this hypergraph has no algebraic structure, no improvement of Erdős' 60-year-old O(n^{r-(1/t^{r-1})}) bound was known for this setting. Futhermore, even in the special case of discs for which the semialgebraic structure can be used, our result improves the best known result by a factor of Ω̃(n^{(2r-2)/(3r-2)}). To obtain our results, we use the recently improved results for the graph Zarankiewicz’s problem in the corresponding settings, along with a variety of combinatorial and geometric techniques, including shallow cuttings, biclique covers, transversals, and planarity.
@InProceedings{chan_et_al:LIPIcs.SoCG.2025.33, author = {Chan, Timothy M. and Keller, Chaya and Smorodinsky, Shakhar}, title = {{On Zarankiewicz’s Problem for Intersection Hypergraphs of Geometric Objects}}, booktitle = {41st International Symposium on Computational Geometry (SoCG 2025)}, pages = {33:1--33:14}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-370-6}, ISSN = {1868-8969}, year = {2025}, volume = {332}, editor = {Aichholzer, Oswin and Wang, Haitao}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2025.33}, URN = {urn:nbn:de:0030-drops-231850}, doi = {10.4230/LIPIcs.SoCG.2025.33}, annote = {Keywords: Zarankiewicz’s Problem, hypergraphs, intersection graphs, axis-parallel boxes, pseudo-discs} }
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