English

Intermediate subgroups of braid groups are not bi-orderable

Geometric Topology 2025-10-30 v1 Algebraic Topology

Abstract

Let MM be the disk or a compact, connected surface without boundary different from the sphere S2S^2 and the real projective plane RP2\mathbb{R}P^2, and let NN be a compact, connected surface (possibly with boundary). It is known that the pure braid groups Pn(M)P_n(M) of MM are bi-orderable, and, for n3n\geq 3, that the full braid groups Bn(M)B_n(M) of MM are not bi-orderable. The main purpose of this article is to show that for all n3n \geq 3, any subgroup HH of Bn(N)B_n(N) that satisfies Pn(N)HBn(N)P_n(N) \subsetneq H \subset B_n(N) is not bi-orderable.

Keywords

Cite

@article{arxiv.2510.24947,
  title  = {Intermediate subgroups of braid groups are not bi-orderable},
  author = {R. M. de A. Cruz},
  journal= {arXiv preprint arXiv:2510.24947},
  year   = {2025}
}

Comments

14 pages, 1 figure

R2 v1 2026-07-01T07:10:35.538Z