English

Meromorphic Hodge moduli spaces for reductive groups in arbitrary characteristic

Algebraic Geometry 2025-04-02 v2

Abstract

Fix a smooth projective family of curves CSC \to S and a split reductive group scheme GG over a Noetherian base scheme SS. For any (possibly nonreduced) fixed relative Cartier divisor DD, we provide a treatment of the moduli of GG-bundles on the fibers of CC equipped with tt-connections with pole orders bounded by DD. Under mild assumptions on the characteristics of all the residue fields of SS, we construct a Hodge moduli space MHod,GAS1M_{Hod, G} \to \mathbb{A}^1_S for the semistable locus, construct a Harder-Narasimhan stratification, and thus obtain a semistable reduction theorem. If all the fibers of the divisor of poles DD are nonempty, then we show that the stack of semistable objects is smooth over AS1\mathbb{A}^1_{S}. We also define a Hodge-Hitchin morphism in positive characteristic and prove that it is proper.

Keywords

Cite

@article{arxiv.2307.16755,
  title  = {Meromorphic Hodge moduli spaces for reductive groups in arbitrary characteristic},
  author = {Andres Fernandez Herrero and Siqing Zhang},
  journal= {arXiv preprint arXiv:2307.16755},
  year   = {2025}
}

Comments

Accepted version. To appear in Mich. Math. J

R2 v1 2026-06-28T11:44:34.610Z