coupled oscillators in network structures. The surface area of a set of sites is defined as the
number of links between the sites within the set and those outside the set. The necessary
condition is that the surface area of any set of c N (0< c< 1) oscillators in the N-oscillator
system must exceed N in the limit N→∞. We also provide the necessary condition for
macroscopic frequency synchronization. Thus, we identify networks in which one or both of …