English

Large normal subgroup growth and large characteristic subgroup growth

Group Theory 2019-06-18 v2

Abstract

The maximal normal subgroup growth type of a finitely generated group is nlognn^{\log n}. Very little is known about groups with this type of growth. In particular, the following is a long standing problem: Let Γ\Gamma be a group and Δ\Delta a subgroup of finite index. Suppose Δ\Delta has normal subgroup growth of type nlognn^{\log n}, does Γ\Gamma has normal subgroup growth of type nlognn^{\log n}? We give a positive answer in some cases, generalizing a result of M\"uller and the second author and a result of Gerdau. For instance, suppose GG is a profinite group and HH an open subgroup of GG. We show that if HH is a generalized Golod-Shafarevich group, then GG has normal subgroup growth of type of nlognn^{\log n}. We also use our methods to show that one can find a group with characteristic subgroup growth of type nlognn^{\log n}.

Keywords

Cite

@article{arxiv.1703.07866,
  title  = {Large normal subgroup growth and large characteristic subgroup growth},
  author = {Yiftach Barnea and Jan-Christoph Schlage-Puchta},
  journal= {arXiv preprint arXiv:1703.07866},
  year   = {2019}
}
R2 v1 2026-06-22T18:54:18.900Z