FIGURE 1. Structure and schematic dynamics of the two networks considered.

a, The co-authorship network. The figure shows the local community structure at a given time step in the vicinity of a randomly selected node. b, As a but for the phone-call network. c, The filled black symbols correspond to the average size of the largest subset of members with the same zip-code, n_real, in the phone-call communities divided by the same quantity found in random sets, n_rand, as a function of the community size, s. Similarly, the open symbols show the average size of the largest subset of community members with an age falling in a three-year time window, divided by the same quantity in random sets. The error bars in both cases correspond to n_real/(n_rand + _rand) and n_real/(n_rand - _rand), where _rand is the standard deviation in the case of the random sets. d, The n_real/s as a function of s, for both the zip-code (filled black symbols) and the age (open symbols). e, Possible events in community evolution. f, The identification of evolving communities. The links at t (blue) and the links at t + 1 (yellow) are merged into a joint graph (green). Any CPM community at t or t + 1 is part of a CPM community in the joined graph, so these can be used to match the two sets of communities.