English

A correspondence of good G-sets under partial geometric quotients

Algebraic Geometry 2016-11-10 v1

Abstract

For a complex variety X^\hat X with an action of a reductive group G^\hat G and a geometric quotient π:X^X\pi: \hat X \to X by a closed normal subgroup HG^H \subset \hat G, we show that open sets of XX admitting good quotients by G=G^/HG=\hat G / H correspond bijectively to open sets in X^\hat X with good G^\hat G-quotients. We use this to compute GIT-chambers and their associated quotients for the diagonal action of PGL2\text{PGL}_2 on (P1)n(\mathbb{P}^1)^n in certain subcones of the PGL2\text{PGL}_2-effective cone via a torus action on affine space. This allows us to represent these quotients as toric varieties with fans determined by convex geometry.

Keywords

Cite

@article{arxiv.1611.02958,
  title  = {A correspondence of good G-sets under partial geometric quotients},
  author = {Johannes Schmitt},
  journal= {arXiv preprint arXiv:1611.02958},
  year   = {2016}
}

Comments

18 pages, comments welcome