English

Pointwise-relatively-compact subgroups and trivial-weight-free representations

Group Theory 2025-06-27 v2 General Topology Representation Theory

Abstract

A pointwise-elliptic subset of a topological group is one whose elements all generate relatively-compact subgroups. A connected locally compact group has a dense pointwise-elliptic subgroup if and only if it is an extension by a compact normal subgroup of a semidirect product LK\mathbb{L}\rtimes \mathbb{K} with connected, simply-connected Lie L\mathbb{L}, compact Lie K\mathbb{K}, with the commutator subgroup K\mathbb{K}' acting on the Lie algebra Lie(L)Lie(\mathbb{L}) with no trivial weights. This extends and recovers a result of Kabenyuk's, providing the analogous classification with G\mathbb{G} assumed Lie connected, topologically perfect, with no non-trivial central elliptic elements.

Keywords

Cite

@article{arxiv.2506.18861,
  title  = {Pointwise-relatively-compact subgroups and trivial-weight-free representations},
  author = {Alexandru Chirvasitu},
  journal= {arXiv preprint arXiv:2506.18861},
  year   = {2025}
}

Comments

v2 corrects a misapplication of a cited reference; 6 pages + references

R2 v1 2026-07-01T03:29:53.038Z