Degree correlations in signed social networks

• Evidence shows that positive networks are assortative, whereas negative ones disassortative.
• We introduce simple models to uncover the relation between sign of links and degree correlations.
• If networks are balanced and split into unequal groups, negative subnetworks are disassortative.
• When unknown, the sign of links can be predicted from the type of degree correlations.

We investigate degree correlations in two online social networks where users are connected through different types of links. We find that, while subnetworks in which links have a positive connotation, such as endorsement and trust, are characterized by assortative mixing by degree, networks in which links have a negative connotation, such as disapproval and distrust, are characterized by disassortative patterns. We introduce a class of simple theoretical models to analyze the interplay between network topology and the superimposed structure based on the sign of links. Results uncover the conditions that underpin the emergence of the patterns observed in the data, namely the assortativity of positive subnetworks and the disassortativity of negative ones. We discuss the implications of our study for the analysis of signed complex networks.