The worst 1-parameter subgroup for toric curve singularities
Kempf proved that when a point is unstable in the sense of geometric invariant theory, there is a "worst" destabilizing 1-parameter subgroup λ. It is natural to ask:
what are the worst destabilizing 1-ps for the unstable points in familiar GIT problems, such as those used to construct the moduli space of curves Mg? We first consider Chow points of rational curves with one unibranch singular point. Then the problem can be restated as an explicit problem in convex geometry (finding the proximum of a polyhedral cone to a point outside it). In computer experiments, we observe that combinatorial features of the worst 1-ps persist as the degree increases. This is joint work with Joshua Jackson (Sheffield).