OPESumExplicit[exp]
calculates OPESum
s.
Overview, OPESum, OPESumSimplify.
[A^iB^(m - i - 3), {i, 0, m - 3}]
OPESum
[%] OPESumExplicit
\sum _{i=0}^{-3+m} A^{\text{iB}^{-3-i+m}}
\sum _{i=0}^{-3+m} A^{\text{iB}^{-3-i+m}}
[a^ib^(j - i) c^(m - j - 4), {i, 0, j}, {j, 0, m - 4}]
OPESum
[%] OPESumExplicit
\sum _{j=0}^{-4+m} \;\text{}\;\text{} (j+1)c^{-j+m-4} a^{\text{ib}^{j-i}}
\sum _{j=0}^{-4+m} \;\text{}\;\text{} (j+1)c^{-j+m-4} a^{\text{ib}^{j-i}}