Figure 1.

Adjacency matrix of a network with two CP pairs. The filled cell or empty cell indicates the presence or absence of an edge, respectively. The solid line indicates the partition of nodes into the two CP pairs. The dashed lines within each CP pair indicate the subpartition of nodes into the core and periphery. Each core block (top-left block in each CP pair) and periphery block (bottom right block in each CP pair) consist of 20 nodes and 40 nodes, respectively. The probability that each pair of nodes is adjacent by an edge is equal to 0.95 within each core block. The same probability is equal to 0.8 between the core and periphery blocks within each CP pair. The same probability is equal to 0.05 within each periphery block and between different CP pairs. We draw edges according to these probabilities, independently for the different node pairs.