The symbolic generic initial system of almost linear point configurations in $\mathbb P^2$

Abstract

Consider an ideal $I \subseteq K[x,y,z]$ corresponding to a point configuration in $\mathbb {P}^2$ where all but one of the points lies on a single line. In this paper, we study the symbolic generic initial system $\{\rm{gin\,}(I^{(m)})\}_m$ obtained by taking the reverse lexicographic generic initial ideals of the uniform fat point ideals $I^{(m)}$. We describe the limiting shape of $\{\rm{gin\,}(I^{(m)})\}_m$ and, in proving this result, demonstrate that infinitely many of the ideals $I^{(m)}$ are componentwise linear.