Dilogarithm

In mathematics, the dilogarithm (or Spence's function), denoted as Li2(z), is a particular case of the polylogarithm.

For |z| ≤ 1, an infinite series also applies (the integral definition constitutes its analytical extension to the complex plane): Alternatively, the dilogarithm function is sometimes defined as In hyperbolic geometry the dilogarithm can be used to compute the volume of an ideal simplex.

[2] He was at school with John Galt,[3] who later wrote a biographical essay on Spence.

The standard choice of branch cut is along the positive real axis

Spence's Function is commonly encountered in particle physics while calculating radiative corrections.