English

Mapping class group actions on configuration spaces and the Johnson filtration

Geometric Topology 2022-05-12 v2 Algebraic Topology General Topology

Abstract

Let Fn(Σg,1)F_n(\Sigma_{g,1}) denote the configuration space of nn ordered points on the surface Σg,1\Sigma_{g,1} and let Γg,1\Gamma_{g,1} denote the mapping class group of Σg,1\Sigma_{g,1}. We prove that the action of Γg,1\Gamma_{g,1} on Hi(Fn(Σg,1);Z)H_i(F_n(\Sigma_{g,1});\mathbb{Z}) is trivial when restricted to the ithi^{th} stage of the Johnson filtration J(i)Γg,1\mathcal{J}(i)\subset \Gamma_{g,1}. We give examples showing that J(2)\mathcal{J}(2) acts nontrivially on H3(F3(Σg,1))H_3(F_3(\Sigma_{g,1})) for g2g\ge 2, and provide two new conceptual reinterpretations of a certain group introduced by Moriyama.

Keywords

Cite

@article{arxiv.2104.09253,
  title  = {Mapping class group actions on configuration spaces and the Johnson filtration},
  author = {Andrea Bianchi and Jeremy Miller and Jennifer C. H. Wilson},
  journal= {arXiv preprint arXiv:2104.09253},
  year   = {2022}
}

Comments

30 pages, 14 figures, to appear in Transactions of the American Mathematical Society

R2 v1 2026-06-24T01:19:28.198Z