English

The well-poised property and torus quotients

Algebraic Geometry 2021-08-27 v3

Abstract

An embedded variety is said to be well-poised when the associated initial ideal degenerations coming from points of the tropical variety are reduced and irreducible. Varieties with a well-poised embedding admit a large collection of explicitly constructible Newton-Okounkov bodies. This paper aims to study the well-poised property under torus quotients. Our first result states that GIT quotients of normal well-poised varieties by quasi-tori also have well-poised embeddings. As an application, we show that several Hassett spaces, M0,β\overline{M}_{0,\beta}, are well-poised under Alexeev's embedding. Conversely, given an affine TT-variety XX with polyhedral divisor D\mathfrak{D} on a well-poised base YY, we construct an embedding of XANX \subseteq \mathbb{A}^N and provide conditions on YY and D\mathfrak{D} which if met, imply XX is well-poised under this embedding. Then we show that any affine arrangement variety meets the specified criteria, generalizing results of Ilten and the second author for rational complexity 1 varieties. Using this result, we explicitly compute many Newton-Okounkov cones of XX and provide a criterion for the associated toric degenerations to be normal. Our final application combines these two results to show that hypertoric varieties have well-poised embeddings.

Keywords

Cite

@article{arxiv.2009.09105,
  title  = {The well-poised property and torus quotients},
  author = {Joseph Cummings and Christopher Manon},
  journal= {arXiv preprint arXiv:2009.09105},
  year   = {2021}
}

Comments

23 pages, new title and abstract, added new material on the well-poised property under GIT quotient