English

Arithmetic representations of mapping class groups

Geometric Topology 2025-05-21 v3 Algebraic Geometry Group Theory

Abstract

Let SS be a closed oriented surface and GG a finite group of orientation preserving automorphisms of SS whose orbit space has genus at least 22. There is a natural group homomorphism from the GG-centralizer in Diff+(S)Diff^+(S) to the GG-centralizer in Sp(H1(S))Sp(H_1(S)). We give a sufficient condition for its image to be a subgroup of finite index and a weaker condition for this to have no finite nonzero orbit (the Putman-Wieland property).

Keywords

Cite

@article{arxiv.2108.12791,
  title  = {Arithmetic representations of mapping class groups},
  author = {Eduard Looijenga},
  journal= {arXiv preprint arXiv:2108.12791},
  year   = {2025}
}

Comments

Minor corrections and improved presentation, to appear in Algebraic & Geometric Topology. 19p

R2 v1 2026-06-24T05:30:05.202Z