English

A lexicographic section of the braid arrangement and the modified Artin presentation

Geometric Topology 2026-01-06 v3 Combinatorics Group Theory

Abstract

We study a specific line arrangement obtained from a generic 22-section of the braid arrangement, and compute the fundamental group of its complement via braid monodromy. We show that the resulting presentation of the fundamental group coincides, under the identification of generators, with the modified Artin presentation introduced by Margalit and McCammond. Moreover, we extend the construction to the Manin--Schechtman arrangements MS(n,k)MS(n, k), which are higher analogues of the braid arrangement. Focusing on the case k=2k = 2, we obtain an explicit presentation of π1(CnMS(n,2))\pi_1(\mathbb{C}^n \setminus MS(n, 2)).

Keywords

Cite

@article{arxiv.2305.18697,
  title  = {A lexicographic section of the braid arrangement and the modified Artin presentation},
  author = {So Yamagata},
  journal= {arXiv preprint arXiv:2305.18697},
  year   = {2026}
}

Comments

18 pages, 10 figures. Replaces the previous version; revised exposition and generalized computations. The title has been changed