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arXiv · 1512.00323

The dual complex of $\bar{M}_{0,n}$ via phylogenetics

Noah Giansiracusa
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Abstract

The moduli space $\bar{M}_{0,n}$ of stable rational n-pointed curves has divisorial boundary with simple normal crossings. In this brief note I observe that the dual complex is a flag complex; that is, a collection of irreducible boundary divisors has nonempty intersection if and only if the pairwise intersections are nonempty. Rather than proving this directly, I translate the statement to a setting in phylogenetics where it is widely used and multiple explicit proofs have been written. It appears this result is known by experts but lacks a detailed reference in the literature, except recently for $n=7$.

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Noah Giansiracusa. 2016-05-09. The dual complex of $\bar{M}_{0,n}$ via phylogenetics. https://arxiv.org/abs/1512.00323

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