English

Explicit Brill-Noether-Petri general curves

Algebraic Geometry 2016-03-15 v3

Abstract

Let p1,,p9p_1,\dots, p_9 be the points in A2(Q)P2(Q)\mathbb A^2(\mathbb Q)\subset \mathbb P^2(\mathbb Q) with coordinates (2,3),(1,4),(2,5),(4,9),(52,375),(5234,37866),(8,23),(43,282),(14,338)(-2,3),(-1,-4),(2,5),(4,9),(52,375), (5234, 37866),(8, -23), (43, 282), \Bigl(\frac{1}{4}, -\frac{33}{8} \Bigr) respectively. We prove that, for any genus gg, a plane curve of degree 3g3g having a gg-tuple point at p1,,p8p_1,\dots, p_8, and a (g1)(g-1)-tuple point at p9p_9, and no other singularities, exists and is a Brill-Noether general curve of genus gg, while a general curve in that gg-dimensional linear system is a Brill-Noether-Petri general curve of genus gg.

Keywords

Cite

@article{arxiv.1511.07321,
  title  = {Explicit Brill-Noether-Petri general curves},
  author = {Enrico Arbarello and Andrea Bruno and Gavril Farkas and Giulia Saccà},
  journal= {arXiv preprint arXiv:1511.07321},
  year   = {2016}
}

Comments

New section added containing an explicit example of a 9-tuple of points in P^2(Q) that are of 3g-general for every g. Added a second proof of the fact that a du Val curve is BN general. Improved exposition

R2 v1 2026-06-22T11:52:16.241Z