# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Scale-Free Networks," by Albert-László Barabási and EricBonabeau. *Scientific American,* May2003, pages 60-69.

Scale-free networks are those in which the relative frequency of nodes with*k* links is proportional to *k*^{-n} for some *n*. Thatis, the links obey a power law. Before there was much research in networks, ithad been assumed that complex networks like the Internet were random, so thatthe distribution of nodes as a function of the number of links was normal.Research has shown, however, that many complex networks, including theInternet, are scale-free. Other examples of scale-free networks are given andthe authors explain the consequences of a network being scale-free.

*--- Mike Breen*