# Social¶

A signed social network graph is a graph whose signed edges represent friendly/hostile interactions between vertices.

A signed social graph for three nodes, where Eve and Bob are friendly with each other and hostile to Alice. This network is balanced because it can be cleanly divided into two subsets, {Bob, Eve} and {Alice}, with friendly relations within each subset and only hostile relations between the subsets.

 structural_imbalance(S[, sampler]) Returns an approximate set of frustrated edges and a bicoloring. Construct the Ising problem to calculate the structural imbalance of a signed social network.