Ting-WeiChao

Given a set of lines in ${\mathbb{R}}^d$, a joint is a point contained in d linearly independent lines. Guth and Katz showed that N lines can determine at most $O(N^{3/2})$ joints in ${\mathbb{R}}^3$ via the polynomial method. Yu and I proved a tight bound on this problem, which also solves a conjecture proposed …