Plus distributions - general form

[alecandido]

We are wondering if it is possible on general grounds to reorganize something of this kind:

using constant coefficients for the distribution part:

If this is possible:

• we are thinking about rewriting our DistributionVec a little in order to collect all the singular bits in a single one (so we will have a fixed amount of components equal to 3 for all orders)
• just do this we only need to:
  • include in coefficient functions definition the log(1-z) ** k / (1-z)
  • multiply in the convolution just for the pdf difference pdf(x/z)/z - pdf(x), that is available since what we currently are doing is multiplying each one of these two terms by a factor that is constant in the second expression (\tilde{c}_k)

[alecandido]

This is exactly what it is done by Vogt in his calculations (e.g.: c2_{ns}^{(3)})

[felixhekhorn]

see #53

[felixhekhorn]

done in #72