ON THE REGULARITY INDEX OF FAT POINTS WHOSE SUPPORT IS CONTAINED IN A LINEAR PROPER SUBSPACE

Abstract We prove the conjecture of Franceschini and Lorenzini [‘Fat points of $\mathbb P^n$ whose support is contained in a linear proper subspace’, J. Pure and Appl. Algebra 160 (2001), 169–182] about the regularity index of fat points of $\mathbb P^n$ whose support is contained in a linear proper subspace.