English

Brill-Noether theory for totally ramified covers of the projective line

Algebraic Geometry 2026-04-30 v1

Abstract

Given a curve CC that is a degree kk cover CP1C \to \mathbb{P}^1 totally ramified at two points pp and qq, we can seek to understand the space of degree dd line bundles on CC with prescribed ramification at pp and qq. The corresponding subschemes of Picd(C)\text{Pic}^d(C) are called transmission loci and are parameterized via elements of the (extended) kk-affine symmetric group Σ~k\widetilde{\Sigma}_k. Transmission loci provide a refinement of the splitting loci that have recently been extensively studied for kk-gonal curves. Pflueger has conjectured analogues of the classic Brill-Noether theorem should hold for transmission loci. In this paper we prove Pflueger's conjectures.

Keywords

Cite

@article{arxiv.2604.26193,
  title  = {Brill-Noether theory for totally ramified covers of the projective line},
  author = {Daksh Aggarwal},
  journal= {arXiv preprint arXiv:2604.26193},
  year   = {2026}
}

Comments

45 pages. Comments welcome