Cascade Dynamics of Multiplex Propagation
  Random links between otherwise distant nodes can greatly facilitate the propagation of disease or information, provided contagion can be transmitted by a single active node. However we show that when the propagation requires simultaneous exposure to multiple sources of activation, called multiplex propagation, the effect of random links is just the opposite: it makes the propagation more difficult to achieve. We calculate analytical and numerically critical points for a threshold model in several classes of complex networks, including an empirical social network. 
Damon Centola (1,2), Michael W. Macy (2), and Victor M. Eguiluz (3)   ((1)Columbia University, (2) Cornell University, (3) I...