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arXiv · 2404.02654

Tropical pseudostable curves

Renzo Cavalieri·Steffen Marcus·Jonathan Wise
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Abstract

We study the tropical version of the contraction morphism $\mathcal{T}$ between moduli spaces of stable and pseudostable curves. By promoting $\mathcal{T}$ 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 $δ_1$ is not contracted to the cone point but mapped onto a ray of $\mathcal{M}_{g,n}^{{\rm trop}, {\rm ps}}$, with a slope reflecting the geometry of the desingularization of a plane cusp. We explore in detail the situation of $g=1$, where the tautological geometry of both spaces is fully described by piecewise polynomial functions on the tropical moduli spaces.

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Renzo Cavalieri, Steffen Marcus, Jonathan Wise. 2024-04-03. Tropical pseudostable curves. https://arxiv.org/abs/2404.02654

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