English

Pullbacks of $\kappa$ classes on $\overline{\mathcal{M}}_{0,n}$

Algebraic Geometry 2020-06-29 v1

Abstract

The moduli space M0,n\overline{\mathcal{M}}_{0,n} carries a codimension-dd cycle class κd\kappa_{d}. We consider the subspace Knd\mathcal{K}^{d}_{n} of Ad(M0,n,Q)A^d(\overline{\mathcal{M}}_{0,n},\mathbb{Q}) spanned by pullbacks of κd\kappa_d via forgetful maps. We find a permutation basis for Knd\mathcal{K}^{d}_{n}, and describe its annihilator under the intersection pairing in terms of dd-dimensional boundary strata. As an application, we give a new permutation basis of the divisor class group of M0,n\overline{\mathcal{M}}_{0,n}.

Cite

@article{arxiv.2006.14996,
  title  = {Pullbacks of $\kappa$ classes on $\overline{\mathcal{M}}_{0,n}$},
  author = {Rohini Ramadas},
  journal= {arXiv preprint arXiv:2006.14996},
  year   = {2020}
}

Comments

11 pages; comments welcome

R2 v1 2026-06-23T16:39:06.356Z