English

Effective faithful tropicalizations associated to linear systems on curves

Algebraic Geometry 2017-04-07 v3

Abstract

For a connected smooth projective curve XX of genus gg, global sections of any line bundle LL with deg(L)2g+1\deg(L) \geq 2g+ 1 give an embedding of the curve into projective space. We consider an analogous statement for a Berkovich skeleton in nonarchimedean geometry, in which projective space is replaced by tropical projective space, and an embedding is replaced by a homeomorphism onto its image preserving integral structures (called a faithful tropicalization). Let KK be an algebraically closed field which is complete with respect to a non-trivial nonarchimedean value. Suppose that XX is defined over KK and has genus g2g \geq 2 and that Γ\Gamma is a skeleton (that is allowed to have ends) of the analytification XanX^{\mathrm{an}} of XX in the sense of Berkovich. We show that if deg(L)3g1\deg(L) \geq 3g-1, then global sections of LL give a faithful tropicalization of Γ\Gamma into tropical projective space. As an application, when YY is a suitable affine curve, we describe the analytification YanY^{\mathrm{an}} as the limit of tropicalizations of an effectively bounded degree.

Keywords

Cite

@article{arxiv.1612.01098,
  title  = {Effective faithful tropicalizations associated to linear systems on curves},
  author = {Shu Kawaguchi and Kazuhiko Yamaki},
  journal= {arXiv preprint arXiv:1612.01098},
  year   = {2017}
}

Comments

85 pages; exposition improved; application to limit of tropicalizations added (v2); minor correction in Theorem 1.7 (v3)