On the number of hyperedges in the hypergraph of lines and pseudo-discs

Abstract

Consider the hypergraph whose vertex set is a family of $n$ lines in general position in the plane, and whose hyperedges are induced by intersections with a family of pseudo-discs. We prove that the number of $t$-hyperedges is bounded by $O_t(n^2)$ and that the total number of hyperedges is bounded by $O(n^3)$. Both bounds are tight.

arXiv commentUpdated version, with minor improvements. 8 pages, 1 figure