English

Stability of normal bundles of Brill-Noether curves

Algebraic Geometry 2024-11-27 v2

Abstract

We prove that the normal bundle of a general Brill-Noether curve of genus g1g \geq 1 and degree dd in Pr\mathbb{P}^r is semistable if g=1g=1 or g5r2r(r1)g\geq \left \lceil \frac{5r}{2}\right\rceil r(r-1), or dd is larger than an explicit function of gg and rr. We further prove that the normal bundle is in fact stable if g2g\geq 2 and either gg or dd satisfy slightly stronger bounds. In particular, for each rr and g1g\geq 1 (respectively, g2g\geq2), there are at most finitely many (d,g)(d,g) for which the normal bundle of the general Brill-Noether curve is not semistable (respectively, stable).

Keywords

Cite

@article{arxiv.2306.12653,
  title  = {Stability of normal bundles of Brill-Noether curves},
  author = {Izzet Coskun and Geoffrey Smith},
  journal= {arXiv preprint arXiv:2306.12653},
  year   = {2024}
}

Comments

Corrected Proposition 3.3 in characteristic 2, improved the exposition and added references. 36 pages