English

Lifting tropical bitangents

Algebraic Geometry 2020-12-16 v2 Combinatorics

Abstract

We study lifts of tropical bitangents to the tropicalization of a given complex algebraic curve together with their lifting multiplicities. Using this characterization, we show that generically all the seven bitangents of a smooth tropical plane quartic lift in sets of four to algebraic bitangents. We do this constructively, i.e. we give solutions for the initial terms of the coefficients of the bitangent lines. This is a step towards a tropical proof that a general smooth quartic admits 28 bitangent lines. The methods are also appropriate to count real bitangents, however the conditions to determine whether a tropical bitangent has real lifts are not purely combinatorial.

Keywords

Cite

@article{arxiv.1708.04480,
  title  = {Lifting tropical bitangents},
  author = {Yoav Len and Hannah Markwig},
  journal= {arXiv preprint arXiv:1708.04480},
  year   = {2020}
}

Comments

35 pages, 24 figures, 1 table. Minor changes. Accepted for publication in Journal of Symbolic Computation

R2 v1 2026-06-22T21:15:03.577Z