Visibility in the plane (Q838444)

We say that \(a\in \mathbb Z ^D\) is visible from \(b\in \mathbb Z ^D\) if there is no element of \(\mathbb Z ^D\) on the straight segment in-between \(a\) and \(b\). In this paper the authors find the size of the smallest subset of the set of integer lattice points, such that every element of a given rectangular grid is visible from our subset, which in particular answers a question of Paul Erdős et al.