English

Factorization semigroups and irreducible components of Hurwitz space. II

Algebraic Geometry 2011-12-07 v2 Group Theory

Abstract

This article is a continuation of the article with the same title (see arXiv:1003.2953v1). Let {\rm HURd,tG(P1)\text{HUR}_{d,t}^{G}(\mathbb P^1)} be the Hurwitz space of degree dd coverings of the projective line P1\mathbb P^1 with Galois group Sd\mathcal S_d and having fixed monodromy type tt consisting of a collection of local monodromy types (that is, a collection of conjugacy classes of permutations σ\sigma of the symmetric group Sd\mathcal S_d acting on the set Id={1,...,d}I_d=\{1,...,d\}). We prove that if the type tt contains big enough number of local monodromies belonging to the conjugacy class CC of an odd permutation σ\sigma which leaves fixed fC2f_C\geq 2 elements of IdI_d, then the Hurwitz space {\rm HURd,tSd(P1)\text{HUR}_{d,t}^{\mathcal S_d}(\mathbb P^1)} is irreducible.

Keywords

Cite

@article{arxiv.1011.3619,
  title  = {Factorization semigroups and irreducible components of Hurwitz space. II},
  author = {Vik. S. Kulikov},
  journal= {arXiv preprint arXiv:1011.3619},
  year   = {2011}
}

Comments

9 pages; the assertion of Theorem 2 is weakened and more detailed proof of Theorem 1 is given. Accepted in Izv. Math

R2 v1 2026-06-21T16:44:24.305Z