English

Tropical pseudostable curves

Algebraic Geometry 2024-04-04 v1

Abstract

We study the tropical version of the contraction morphism T\mathcal{T} between moduli spaces of stable and pseudostable curves. By promoting T\mathcal{T} to a logarithmic morphism, we obtain a piecewise linear function between the generalized cone complexes parameterizing tropical stable and pseudostable curves. The ray corresponding to the contracted divisor δ1\delta_1 is not contracted to the cone point but mapped onto a ray of Mg,ntrop,ps\mathcal{M}_{g,n}^{{\rm trop}, {\rm ps}}, with a slope reflecting the geometry of the desingularization of a plane cusp. We explore in detail the situation of g=1g=1, where the tautological geometry of both spaces is fully described by piecewise polynomial functions on the tropical moduli spaces.

Keywords

Cite

@article{arxiv.2404.02654,
  title  = {Tropical pseudostable curves},
  author = {Renzo Cavalieri and Steffen Marcus and Jonathan Wise},
  journal= {arXiv preprint arXiv:2404.02654},
  year   = {2024}
}

Comments

22 pages, 5 figures. Main text by Renzo Cavalieri and Steffen Marcus. Appendix by Steffen Marcus and Jonathan Wise

R2 v1 2026-06-28T15:42:53.901Z