English

Bredon homological stability for configuration spaces of $G$-manifolds

Algebraic Topology 2023-11-07 v1

Abstract

McDuff and Segal proved that unordered configuration spaces of open manifolds satisfy homological stability: there is a stabilization map σ:Cn(M)Cn+1(M)\sigma: C_n(M)\to C_{n+1}(M) which is an isomorphism on Hd(;Z)H_d(-;\mathbb{Z}) for ndn\gg d. For a finite group GG and an open GG-manifold MM, under some hypotheses we define a family of equivariant stabilization maps σG/H:Cn(M)Cn+G/H(M)\sigma_{G/H}:C_n(M)\to C_{n+|G/H|}(M) for HGH\leq G. In general, these do not induce stability for Bredon homology, the equivariant analogue of singular homology. Instead, we show that each σG/H\sigma_{G/H} induces isomorphisms on the ordinary homology of the fixed points of Cn(M)C_n(M), and if the group is Dedekind (e.g. abelian), we obtain the following Bredon homological stability statement: HdG(n0Cn(M))H^G_d(\bigsqcup_{n\geq 0}C_n(M)) is finitely generated over Z[σG/H:HG]\mathbb{Z}[\sigma_{G/H} : H\leq G]. This reduces to the classical statement when G=eG=e.

Keywords

Cite

@article{arxiv.2311.02459,
  title  = {Bredon homological stability for configuration spaces of $G$-manifolds},
  author = {Eva Belmont and J. D. Quigley and Chase Vogeli},
  journal= {arXiv preprint arXiv:2311.02459},
  year   = {2023}
}

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