English

Galois subspaces for compact Riemann surfaces of genus 2

Algebraic Geometry 2026-03-31 v1

Abstract

Let XX be a compact Riemann surface of genus 2 and DD a very ample divisor with ϕD\phi_D its associated embedding into Pn\mathbb{P}^{n}. We consider the set GX,DG_{X,D} of linear subspaces WW of Pn\mathbb{P}^n of codimension 22 with projection πW\pi_W such that fW=πWϕDf_W = \pi_W \circ \phi_D is Galois, i.e. fWk(P1)k(X)f_W^*k(\mathbb{P}^1) \subseteq k(X) is a Galois extension. It is known that GX,DG_{X,D} is isomorphic to a disjoint union of projective spaces. In this article, we calculate the dimension of projective spaces in the decomposition of GX,DG_{X,D}, when DD is induced by a subgroup of Aut(X)\mathrm{Aut}(X).

Keywords

Cite

@article{arxiv.2603.27431,
  title  = {Galois subspaces for compact Riemann surfaces of genus 2},
  author = {Juan-Pablo Llerena-Córdova},
  journal= {arXiv preprint arXiv:2603.27431},
  year   = {2026}
}

Comments

9 pages and 5 tables. Comments are welcomed