English

Trigonal Curve with Trigonal Deformation of Maximal Rank

Algebraic Geometry 2025-11-06 v3

Abstract

By extending methods of Favale-Pirola arXiv:2108.02157 and Gonz\'alez-Alonso-Torelli arXiv:2402.15158 to toric surfaces via toric Jacobian ring, we are able to show there exists trigonal curve with trigonal deformation of rank gg for g=5,7,9,11,13,15g=5,7,9,11,13,15 by giving an explicit example. Also, we give a computable criterion to determine whether a nondegenerate ample section of toric surface has first order deformation of rank gg within the linear system.

Keywords

Cite

@article{arxiv.2506.11450,
  title  = {Trigonal Curve with Trigonal Deformation of Maximal Rank},
  author = {Jiacheng Zhang},
  journal= {arXiv preprint arXiv:2506.11450},
  year   = {2025}
}

Comments

19 pages. Minor Changes. Comments are welcomed!