Existence of Higher Extremal K\"ahler Metrics on a Minimal Ruled Surface

Abstract

In this paper we prove that on a special type of minimal ruled surface, which is an example of a `pseudo-Hirzebruch surface', every K\"ahler class admits a certain kind of `higher extremal K\"ahler metric', which is a K\"ahler metric whose corresponding top Chern form and volume form satisfy a nice equation motivated by analogy with the equation characterizing an extremal K\"ahler metric. From an already proven result, it will follow that this specific higher extremal K\"ahler metric cannot be a `higher constant scalar curvature K\"ahler (hcscK) metric', which is defined, again by analogy with the definition of a constant scalar curvature K\"ahler (cscK) metric, to be a K\"ahler metric whose top Chern form is harmonic. By doing a certain set of computations involving the top Bando-Futaki invariant we will conclude that hcscK metrics do not exist in any K\"ahler class on this surface.