The generalized polylogarithm, also called the Goncharov polylogarithm, is an iterated integral defined recursively by
where . For a list of
zeros, the normalization is
The integral can initially be taken along a positive real segment that avoids the nonzero .
Its other branches are obtained by analytic
continuation along paths avoiding 0 and the nonzero
(Goncharov 2001). For positive
integer
, the ordinary polylogarithm
equals
for
. Restricting the indices to
,
,
and
also gives the harmonic polylogarithm,
with a factor of
for each index equal to 1.
The generalized polylogarithm is implemented in the Wolfram Language as GeneralizedPolyLog[{a1, ..., ak}, z].