Computing the Variance of the Spectral Numbers (SN)

In his talk, Hertling conjectured that

variance(SN) <= (SN_max - SN_min) / 12 .

We compute

g(f) := mu(f) * ((SN_max - SN_min) - 12*variance(SN)) .

• for semiquasihomogeneous singularities.
• for Newton nondegenerate singularities.
• for Newton degenerate singularities.