Lorenz curves in the model without treatment.

<p>The results are for populations with different variances in partner change rates, <i>σ</i>², and the mean rate of partner change kept constant. The diagonal line represents the situation in which every risk group would have the same HIV prevalence. Lorenz curves deviate from it which means that the distributions of infection across the risk groups for proportionate, intermediate and assortative mixing are skewed with high prevalence in small high risk groups. This effect gets stronger as the mixing becomes more assortative. Note that we did not plot the results for the parameters used in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005012#pcbi.1005012.g003" target="_blank">Fig 3</a> for which HIV is not able to spread (yellow curves for all levels of mixing and the green curve for proportionate mixing).