# psiDivisorM0nbar -- returns the class of the divisor $\Psi$

## Description

Let $U$ be the universal family over $M=\bar{M}_{0,n}$, let $\omega_{U/M}$ be the relative dualizing sheaf, and let $\sigma_i: M \rightarrow U$ be the sections defining the marked points. The divisors $\psi_i$ are defined by $\psi_i := \sigma_i^*(\omega_{U/M})$. We define the class $\Psi$ by $\Psi = \psi_1 + ... + \psi_n.$

 i1 : psiDivisorM0nbar(14) 24 33 40 45 48 49 o1 = --*B + --*B + --*B + --*B + --*B + --*B 13 2 13 3 13 4 13 5 13 6 13 7 o1 : S_14-symmetric divisor on M-0-14-bar

## Ways to use psiDivisorM0nbar :

• "psiDivisorM0nbar(ZZ)"

## For the programmer

The object psiDivisorM0nbar is .