Peeling the Grid

Abstract

Consider the set of points formed by the integer $n \times n$ grid, and the process that in each iteration removes from the point set the vertices of its convex-hull. Here, we prove that the number of iterations of this process is O(n^{4/3}); that is, the number of convex layers of the $n\times n$ grid is \Theta(n^{4/3}).