[graph-tool] Understanding the Model Function for Generative model

With the reference to the paper on the generative models ---- " https://arxiv.org/pdf/1705.10225.pdf " It is supposed to be an introductory publication on the generative model idea used in graph-tool but I am having little difficulty in understanding the equation 4, the model generating function using Lagrange Multiplier. A little more explanation of how this equation arrived, will be very much helpful. A reference to further reading to understand this will also be very helpful. -- Sent from: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/