SymmetricDivisorM0nbar + SymmetricDivisorM0nbar -- add two $S_n$ symmetric divisors

Synopsis

Operator: +
Usage:

D+E
Inputs:
- D, an instance of the type SymmetricDivisorM0nbar
- E, an instance of the type SymmetricDivisorM0nbar
Outputs:
- F, an instance of the type SymmetricDivisorM0nbar

Description

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

i1 : D=symmetricDivisorM0nbar(6,{1/2,1/3})

     1      1
o1 = -*B  + -*B
     2  2   3  3

o1 : S_6-symmetric divisor on M-0-6-bar

i2 : E=symmetricDivisorM0nbar(6,2*B_2+3*B_3)

o2 = 2*B  + 3*B
        2      3

o2 : S_6-symmetric divisor on M-0-6-bar

i3 : D+E

     5      10
o3 = -*B  + --*B
     2  2    3  3

o3 : S_6-symmetric divisor on M-0-6-bar