# - SymmetricDivisorM0nbar -- negate a symmetric divisor

## Description

Let $Pic(\bar{M}_{0,n})_Q^{S_n}$ denote the vector space of $S_n$-invariant divisors with rational coefficients. Here, given an $S_n$ symmetric $Q$-divisor $D$ on $\bar{M}_{0,n}$, the function returns $-D$.

 i1 : D=symmetricDivisorM0nbar(6,{2,3}) o1 = 2*B + 3*B 2 3 o1 : S_6-symmetric divisor on M-0-6-bar i2 : E=-D o2 = - 2*B - 3*B 2 3 o2 : S_6-symmetric divisor on M-0-6-bar