PreprintarXiv licencearXiv
The integral Chow rings of 𝒜3 and ℳ3
Abstract
Over ℂ, we compute the integral Chow ring of 𝒜3, the moduli stack of principally polarized abelian threefolds. Along the way, we compute the integral Chow ring of ℳ3, the moduli stack of smooth genus-three curves. The ring CH(𝒜3) is generated by the Chern classes of the Hodge bundle, along with three classes supported on the locus of decomposable abelian varieties, subject to 16 relations. The ring CH(ℳ3) is generated by the Chern classes of the Hodge bundle, with five relations. In particular, we find that the top Chern class of the Hodge bundle, λ3, has order 504 on 𝒜3 and 252 on ℳ3. For 𝒜3, this removes the factor of 4 from the bound 252|ord(λ3)| 1008 of Ekedahl and van der Geer.
Related
- Ambient Chow Rings of Debarre--Voisin Fourfolds and the Beauville--Voisin Conjecture
- Building sets, Chow rings, and their Hilbert series
- A Fan Algorithm for Chow-Witt Rings of Smooth Projective Toric Varieties
- Integral coefficient rings and homological dimensions of algebras
- A compactness theorem for twisted-unitary elements of integral group rings, with a certified route to the theta-unitary Case A at window B(4) of the Promislow group
BibTeX
@misc{bishop2026integral,
title = {{The integral Chow rings of $\mathcal A_3$ and $\mathcal M_3$}},
author = {Emma Bishop},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.06014},
eprint = {2611.06014},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.06014},
}
RIS
TY - UNPB
TI - The integral Chow rings of 𝒜_3 and ℳ_3
AU - Emma Bishop
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.06014
UR - https://arxiv.org/abs/2611.06014
AB - Over ℂ, we compute the integral Chow ring of 𝒜_3, the moduli stack of principally polarized abelian threefolds. Along the way, we compute the integral Chow ring of ℳ_3, the moduli stack of smooth genus-three curves. The ring CH(𝒜_3) is generated by the Chern classes of the Hodge bundle, along with three classes supported on the locus of decomposable abelian varieties, subject to 16 relations. The ring CH(ℳ_3) is generated by the Chern classes of the Hodge bundle, with five relations. In particular, we find that the top Chern class of the Hodge bundle, λ_3, has order 504 on 𝒜_3 and 252 on ℳ_3. For 𝒜_3, this removes the factor of 4 from the bound 252|ord(λ_3)| 1008 of Ekedahl and van der Geer.
ER -