PreprintCC BY 4.0arXiv
Open substacks preserving moduli spaces: classification and bounds
Abstract
For a smooth locally reductive stack admitting an adequate moduli space, we show that there are finitely many open substacks preserving the adequate moduli space, and give a complete classification of such opens. For ๐พm-actions, this becomes an explicit description in terms of the codimension-one Bialynicki-Birula strata. Moreover, for a stable adequate moduli space, we show that the number of preserving opens are bounded by 3 raised to the relative Picard rank. As an application, the number of fixed components for ๐พm-actions is at least the relative Picard rank.
Related
- Finiteness of open substacks with proper moduli spaces
- FeatureZ: A General Framework for Feature-Preserving Compression via Pointwise Bounds and Star Classification
- Cetraro lectures on integrable systems and moduli spaces of curves
- Birational maps of moduli spaces of stable sheaves on a K3 surface induced by Fourier-Mukai transforms
- Compactification of parabolic Hermitian--Einstein moduli spaces on complex surfaces
BibTeX
@misc{wang2026open,
title = {{Open substacks preserving moduli spaces: classification and bounds}},
author = {Jianping Wang and Xucheng Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.15831},
eprint = {2610.15831},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.15831},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Open substacks preserving moduli spaces: classification and bounds
AU - Jianping Wang
AU - Xucheng Zhang
PY - 2026
DA - 2026/10/11
PB - arXiv
DO - 10.48550/arxiv.2610.15831
UR - https://arxiv.org/abs/2610.15831
AB - For a smooth locally reductive stack admitting an adequate moduli space, we show that there are finitely many open substacks preserving the adequate moduli space, and give a complete classification of such opens. For ๐พ_m-actions, this becomes an explicit description in terms of the codimension-one Bialynicki-Birula strata. Moreover, for a stable adequate moduli space, we show that the number of preserving opens are bounded by 3 raised to the relative Picard rank. As an application, the number of fixed components for ๐พ_m-actions is at least the relative Picard rank.
ER -