Chow classes of divisors on stacks of pointed hyperelliptic curves

Abstract

We calculate the classes of the universal hyperelliptic Weierstrass divisor $\bar{{\mathcal H}}_{g,w}$ and the universal $g^1_2$ divisor $\bar{{\mathcal H}}_{g,g^1_2}$. Our results are expressed in terms of a basis for $Cl(\bar{{\mathcal H}}_{g,1})$ and $Cl(\bar{{\mathcal H}}_{g,2})$ computed by Scavia.