3 problems

Weak Dirac conjecture. Every set $\mathcal{P}$ of $n$ non-collinear points in the plane contains a point incident to at least

Let $P$ be a set of $n$ points in $mathbb C^2$. Say that points are collinear when they lie on one line. Three-point-line conjecture. There exists a constant $c>0$ such that, if at…

Let $e_2(n)$ be the minimum number of ordinary lines determined by $n$ points, and let $n_0$ be the threshold appearing in the source's theorem giving the exact values of $e_2(n)$.…