Betti numbers and linear covers of points

Hailong Dao, Ben Lund, Sreehari Suresh-Babu

We prove that for a finite set of points $X$ in the projective $n$-space over any field, the Betti number ${\hat{I}}_{n,n+1}^2$ of the coordinate ring of $X$ is non-zero if and only if $X$…