English

On some fibrations of $\overline{M}_{0,n}$

Algebraic Geometry 2011-05-18 v1

Abstract

The paper is a second step in the study of M0,n\overline{M}_{0,n} started in arXiv:1006.0987 [math.AG]. We study fiber type morphisms of this moduli space via Kapranov's beautiful description. Our final goal is to understand if any dominant morphism f:M0,nXf: \overline{M}_{0,n} \to X with positive dimensional fibers factors through forgetful morphisms. We prove that this is true if either n7n \leq 7 or dimX2\rm {dim} X \leq 2 or the rational map induced on Pn3P^{n-3} has linear general fibers. Along the way we give examples of forgetful morphisms whose fibers are connected curves of arbitrarily high positive genus, for n>>0n>>0.

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Cite

@article{arxiv.1105.3293,
  title  = {On some fibrations of $\overline{M}_{0,n}$},
  author = {Andrea Bruno and Massimiliano Mella},
  journal= {arXiv preprint arXiv:1105.3293},
  year   = {2011}
}

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23 pages