Boundary Expression for Chern Classes of the Hodge Bundle on Spaces of Cyclic Covers

Bryson Owens, Seamus Somerstep

Published 2019-12-16Version 1

We compute an explicit formula for the first Chern class of the Hodge Bundle over the space of admissible cyclic $\mathbb{Z}/3\mathbb{Z}$ covers of $n$-pointed rational stable curves as a linear combination of boundary strata. We then apply this formula to give a recursive formula for calculating certain Hodge integrals containing $\lambda_1$. We also consider covers with a ${\mathbb{Z}}/{2\mathbb{Z}}$ action for which we compute $\lambda_2$ as a linear combination of codimension two boundary strata.