Wall-crossing for K-moduli spaces of certain families of weighted projective hypersurfaces

TL;DR

This paper studies the structure and wall-crossing behavior of K-moduli spaces of certain weighted hypersurfaces, revealing their birational models and stability limits in algebraic geometry.

Contribution

It explicitly describes the wall crossing phenomena for K-moduli spaces of weighted hypersurfaces and connects these to GIT variation and birational models.

Findings

K-polystable limits are also weighted hypersurfaces in the same space

Wall crossing coincides with GIT variation except at the last wall

Provides new birational models for loci in hyperelliptic curve moduli

Abstract

We describe the K-moduli spaces of weighted hypersurfaces of degree $2(n+3)$ in $\mathbb{P}(1,2,n+2,n+3)$. We show that the K-polystable limits of these weighted hypersurfaces are also weighted hypersurfaces of the same degree in the same weighted projective space. This is achieved by an explicit study of the wall crossing for K-moduli spaces $M_w$ of certain log Fano pairs with coefficient $w$ whose double cover gives the weighted hypersurface. Moreover, we show that the wall crossing of $M_w$ coincides with variation of GIT except at the last K-moduli wall which gives a divisorial contraction. Our K-moduli spaces provide new birational models for some natural loci in the moduli space of marked hyperelliptic curves.